More of a text dump than an actual guide, but read it anyways.

Introduction

What is an AD Carry?
An Attack Damage (AD) Carry for the purposes of this guide is a champion that can deal tons of damage consistently via auto-attacks, and can also do the most damage to structures. How some champions do this best using their abilities and damage type varies, but the basic concept is the same.

Sounds sweet! Why wouldn't I play one!
Hold on there cowboy! You can't just go out there right now and destroy the enemy. Ability Power (AP) champions do that instead with their spell combos, but most of them suffer from lack of damage late game. They simply don't scale or keep up as well as an AD carry would.

Wait, what's the catch?
The catch with AD carries is that they start out fairly weak in the beginning of the game. That's not to say they can't get kills, but it's unlikely that they can score kills on their own. And you have to work to becoming the power house you are late game.

I'm confused :< Explain plz.
Due to how the game works, champions gain the most damage output from buying AD items. To get those items, you need gold. And to get gold, you need to be able to kill creeps/minions and kill champions. Or wait a really long time, but that's not preferred.

But wouldn't that make everyone an AD carry?
Technically it does if they get enough items, but they aren't design for that role, and thus they will most likely lose to champions that are meant to be AD carries. AD carries have abilities to further increase their damage output with a high AD stat; they are known as steroids. AD carries also have a high auto-attack range, so they have a much higher degree of safety and freedom on who they want to auto-attack.

Okay, so I'm killing creeps and I'm not getting any gold. What gives?
In order to earn gold, you have to deal the killing blow to the creep. This is known as last-hitting. You can just mindlessly auto-attack and hope for a killing blow, but good players can get the last-hit on every creep! The number of creeps you kill is called your creep score, or CS for short. Generally the higher your CS, the more gold you have earned.

I just tried to kill a champion but it's not working!
Oh boy really? Unfortunately, I can only really tell you how to kill a champion in general vague terms without knowing more about your situation. It's a case-by-case basis. You can ask questions about that if you want, but for now this is beyond the scope of this thread.

Fine, how do you get a high CS?
To get a high CS, you have to understand how auto-attacking works. Initially, your champion is ready to attack something you command it to, given that your champion is in range. Once he does attack something however, he must wait for a moment before he can attack again. This is known as his attack speed (AS), and in early levels it is very slow. However, as long as you don't attack for a little while, your champion will be ready to attack at a moment's notice. Wouldn't it be nice if you could time that attack to get the killing blow on a creep? It turns out that you can. Just wait until its health is low enough for you to kill it in one blow. One. Attack. That is all it takes to increase your CS.

But the other dude is pushing the creeps into my turret, and the turret is KSing me!
Either respond like-wise, or learn how to CS under your turret. As a general rule of thumb, it takes two turret shots and one attack from your AD carry to kill a melee creep, and one turret shot and two attacks from your AD carry to kill a ranged creep. Note that siege minions take 50% reduced damage from turrets, so be sure to take that into account when judging when to time your last hit.

Yes, it is annoying to get pushed into your turret, but the enemy that does this may make themselves very vulnerable to ambushes (aka ganks). The longer the enemy keeps pushing into your turret, the more likely your teammates will come by and gank them. The jungler on your team is usually supposed to do this when possible.

How do I get my champion to stop attacking creeps?
Your champion won't auto-attack creeps if he or she is told to move. This is generally the preferred method, since many champion abilities are skillshots, and it's a lot easier to hit someone that's not moving. Also, if you're moving randomly, there's very little that the opposing players can do to predict your movements and land skillshots reliably. Keyword: randomly.

Alternatively, you can tell your champion to stop (default 's' key), which makes him/her stop doing anything at all.

CSing is hard =( I keep missing most of the creeps.
Unfortunately, CSing in concept is easy, but mastery of it is very difficult. All I can say is to practice practice practice! Be mindful of your position if you see a potential last hit, as sometimes you may find yourself clicking on a creep, only to lose it because your champion was not in position to attack it.

Intermediate Laning Stuff

Goddamnit how do the good players get all the CS!
By being really good at CSing! However, there are techniques to help ensure that you get more CS outside of simply last-hitting.

Secret techniques? Why didn't you tell me about them before!
Because they're not easy. Well, except last-hitting under your turret, but ideally you never have to do that in the first place, since the turret is very good at KSing. The vast majority of techniques require you to damage the creeps prematurely, which flies directly against the discipline of last-hitting. But in general, all of them manipulate the lane in one way or another.

Manipulate the lane...?
The position of the creep battle (to be known as the creep line), and the presence/absence of champions. I'll describe zones and understanding the benefits/disabilities of any particular zone.

Oh, I think I've heard of zoning before. What is it?
The act of zoning is to discourage people from going some place, most commonly close to the creeps or near the grass that's found in the lanes. When zoning someone, you're usually threatening them with a dire consequence for getting too close (e.g. Blitzcrank grabs you from the grass), or otherwise harassing them. To zone someone away from the creeps as to deny them experience gains is the ultimate form of zoning.

It is important to remember that zoning is only effective if you can convince your opponents to stay away from the area you're trying to zone. This means you can pull off some pretty intricate stuff, such as zoning someone from the bush, even though you have already recalled and are buying items at your fountain. In addition, the bush can play a great role in zoning. However, this advantage can be negated if a ward is placed in the bush. For example, Alistar can potentially zone you out if he camps in the bush next to the creep line, but if you're Caitlyn or Kog'Maw, you can zone him instead with long ranged auto-attacks.

Usually the AD carry does not have the tools to zone effectively. Certain champions such as supports or casters may have powerful zoning tools, such as a root or stun. Other champions, including the AD carry if fed, can zone with sheer damage. And many champions can be zoned if threatened with death.

Okay, what about the disabilities of zoning?
You're confused. When I say "zones", I mean particular areas of the lane between your outer turret, and their outer turret. But there are drawbacks to zoning as well, such as getting caught out of position when the enemy team ganks you.

What are these zones in a lane?
There are benefits and drawbacks to being in any particular area of the map. The lane is no exception. Obviously if you're next to your turret, it will discourage your opponents from attacking you, thus protecting you. However, the turret will KS any creeps in its area of attack, so you'll be missing out on CS.

The next zones of interest are the proximate areas around the two patches of grass in the lane, mainly because of the zoning potential. Being on your side of the map while in the lane gives you a better chance of escaping gank attempts with your life, while being on their side of the map really opens you up to ganks. However, these zones are also important in that different gank opportunities arise. This will really show if you're playing against mid-high elo opponents. For instance, if you're on blue team's bottom lane, your half of the lane can be a bit difficult to gank due to the lack of places for the ganker to hide in, but at the same time there is a direct route to cut you off from safety, which rewards more aggressive gankers. On the other hand, if you're on the purple team's bottom lane, that half of the lane gives gankers a convenient place to hide, but there isn't a good route to cut off escapes if your victims are on their half of the map. And in either case, gankers can appear unexpectedly from the lane's two lines of brush.

The last zone of interest is the surrounding area, which is where gankers and junglers come from. There are various areas to ward, and while it may be impractical to watch all possible approaches, there are different benefits and reasons for warding the possible areas. Obviously you run the risk of getting jumped on when going out there to place a ward, but the benefits are very worthwhile. Don't stay too long however, as generally this zone is outside of the range of exp gains.

That's cool and all, but how does most of this help me CS?
Most of the ganking business is about shutting down the opponent. You don't need perfect CSing to win the game, but having a better CS and gold than your opponent is usually the mark to aim for. By not getting ganked and setting them up for ganks, you have a better chance of winning.

Are there other ways to beat their CS?
Other than killing them, yes there is. Pushing the creep line to their turret causes your creeps to get killed by turret fire, and the enemy will lose out on CS. But as you may have guessed, being this far out from your turret is also asking to get ganked. But there's a silver lining in this! This is generally a good time to recall and buy items. By the time you finish buying items and returning to the lane, the creep line will have moved back towards your side of the map. As with many things in League of Legends, do this in moderation, as every time you recall, you are missing out on experience and CS.

There's some luck and skill involved in this technique, and there's an uncommon chance that it may backfire. Also, be aware that certain champs have the power to push the creep line into your turret, even if you recall, buy items, and run back to lane as fast as possible. In situations like these, it would be wise to have one champion stay behind to defend and manage the creep line. When you are done with buying, then your lane partner can recall and buy his/her items.

Wait, this sounds like it applies to all champs, I thought this was about the AD carry?
It applies the most to the AD carry, because his potential grows the most with items, as I have explained earlier. This is worth reiterating.

Advanced Laning Stuff

Fair enough. Any more techniques related to CSing?
I suppose I should tell you about pulling. Assuming you and your lane opponents are doing their share of last-hitting, the amount of push and pull on the creep line will be roughly the same. However, while it is convenient to last-hit when you can, there is a particular window of opportunity where you can still score the last hit on a creep while it is being attacked by the other creeps. Scoring the killing blow at the last possible moment (or not at all for that matter) increases the longevity of their creeps over your own creeps, which translates into their creeps pushing the lane even more than your own creeps. This means that you'll influence the creep line to move towards your turret.

Wait, why would I pull my lane!?
Two reasons. The first one is important if you're very vulnerable to a gank due to being very far away from the safety of your own turret. The second one is to help set up lane freezing.

Lane freezing? What's that?
The holy grail of ideal laning conditions. Basically, you alter and influence the lane in such a way that the creep line stays where you want it to. To freeze a lane in your favor, you have to keep an eye out for certain conditions. The main condition is to have the enemy creep wave have the pushing advantage, but only moderately. This way, you can still get last hits, while the creep line slowly moves towards your side of the map. Depending on how much you intervene and attack/last-hit, you can adjust and compensate for how much the creep waves push at each other. When you move the creep line to being just outside of your turret range, then you have reached maximum safety while still allowing you the best chance to get high CS (most of the time).

However, this is an insanely difficult balancing act: any large imbalance in pushing power for either side of the lane results in the creep line shifting, and that includes the enemy champions trying to CS. And if your creeps become too numerous for the opposing creeps to handle, there's no way to stop it from approaching the turret other than having the opposing champions intervene. And they decide when they want to do that. Worst case scenario, your lane opponents freeze the lane right in front of their turret.

On a special note, you can use your own champion to draw creep aggro and stop them from moving into your turret's attack range, but you will suffer damage. As the AD carry, the price you pay for lane freezing in this manner can be alleviated somewhat with lifesteal and armor. And if you rush Wriggle's Lantern, it is a very good tool for lane freezing. Champions with naturally high AD such as Fiora are also better at lane freezing.

Argh! I can't master lane freezing! They keep messing it up!
It's actually pretty easy to disrupt if the enemy champions are inclined to do so.

I'm getting a good amount of CS... I think?
A good measure of how well you're doing in CS is to check out your CS and your opponent's by the 10 minute mark. Why 10 minutes? Because the elements of laning will have been applied already, but this is before all the chaos and entropy of team fights, migrations, and other things that would detract from your time spent at CSing. 100 CS is nearly perfect CS.

I'm still missing 30 CS from that number!
Assuming it's not lack of skill on your part, I assume this may have partly to do with you getting zoned, or there's a lot of aggressive trading, or double jeopardy.

Double jeopardy?
Okay I'll be honest, it's a term I made up. Double jeopardy is when there's two creeps that are ready for you to kill, but you don't have time to kill them both. You could use abilities and spells to secure that CS, but it's not ideal. Preventing double jeopardy requires a lot of foresight and some luck, and will require you to attack the creeps in such a way as to stagger their times of death, as opposed to having them die at the same time.

For example, if there's four ranged creeps attacking two melee creeps with attacks equally split, and both melee creeps have the same health, then a double jeopardy will happen if you don't do something. Preventing a double jeopardy in this case can be as simple as auto-attacking one of the creeps, but don't forget to time your auto-attacks so you can still score the last hit. Due to the number of creeps spawned per wave, it is extremely unlikely for a double jeopardy to occur on the first wave. But as lane conditions change, be vigilant.

We destroyed their turret at 8 minutes into the game! We da bomb!
Uh oh! That is actually a bad thing!

Huh? How is that a bad thing?
I'm not going to deny that it opens up your options a bit by giving you more places to roam. However, the effective lane length where the creep line can migrate has doubled, extending into enemy territory. This means there's twice as many areas where they can gank from, which require nearly twice as much ward coverage to watch, and the distance you have to run to safety has also increased dramatically. This is unsafe, and you need that gold and CS! Meanwhile on the flip side of the coin, the enemy gets a lane where they can enjoy safer laning benefits.

Wait, so we shouldn't ever destroy their tower? I'm confused.
You'll have to destroy it eventually. As a general rule of thumb, it's okay to destroy it when you have at least one major AD item (e.g. Infinity Edge) or you're well on your way to buying one, as by then you'll have some damage you can contribute to team fights and skirmishes. Early game damage is defined by creep aggro and damage from abilities, while late game damage caters more to the AP carry and AD carry.

There's also other dynamics to the game that dictate that the outer tower must fall eventually. Turrets get stronger and stronger the closer to the Nexus you get, but their defenses decay over time. Champions get stronger over time, and a good number of melee champions have a higher probability to tower dive you successfully as they gain levels and items. Outer turrets, compared to inner turrets and inhibitor turrets, are not very safe for that reason.

Not Laning Phase and Everything Else

Oh my gawd I take too much damage and I have to recall too much!
Champion have different methods of surviving and extending their useful time outside of the fountain. Nearly every melee champion has self-healing of some sort, AP champions generally have superior range that keeps them safe, and AD carries can sustain themselves with lifesteal. Lifesteal is an essential stat to have once you've built up enough AD, and will allow you to survive fights better. Usually during mid game, you can make anything in the jungle your HP regeneration machine and auto-attack them down for some health. Exceptions to this are Baron Nashor and dragon; they simply deal too much DPS while debuffing your own DPS. Late game however you can take dragon by yourself.

That's fine and all that, but I get blown up during a team fight and I can't do anything!
It's all about positioning. It is true that you'll generally never outrange everything. However, most things that do outrange your auto-attacks are generally not guaranteed to hit you, and they are dodgeable. Frankly, it's okay to be selfish if you're the AD carry, as generally you are built as a glass cannon. Your teammates, especially the ones with CC, are the ones that will enable you to DPS down the enemy team without fear of them annihilating you with their own spells and abilities.

It is extremely difficult to keep track of everything that happens in a fight. Just try your best though. Sometimes it helps to have your own specific plan formulated. For example, you know that Veigar can completely annihilate you and that Alistar can also cause you problems, and you decide that those two champions are the most hazardous to your health. You can try to concentrate on what they do and wing it from there.

Beware that if you're fighting in the jungle and you auto-attack someone, the whole enemy team now has vision of you. This is also true if you auto-attack from the bush during laning phase, and it remains true now.

I still get blown up! Those champions with gap closers are such BS!
In cases like these, I would encourage you to invest in a defensive item or two. A Banshee's Veil is a boon for many AD carries since their biggest vulnerability is getting two-shotted by a caster champion. I offer my sympathies if Akali or Irelia keep getting in your face.

Great! We won a team fight!
Nice! As the AD carry, you are the most potent force in taking team objectives (jungle buffs, dragon, Baron, enemy structures). You can destroy turrets pretty fast, depending on how many items you have farmed up. In addition, you generally contribute the most damage when it comes to taking Baron. Prioritize destroying an enemy inhibitor if you have the chance, otherwise try not to get too carried away smashing their stuff. The worst that can happen is that the enemy team respawns and immediately takes Baron. Let your team know what you can do, and what you want to do by pinging.

I heard Ashe players talk about kiting. What is that?
Kiting is the act of dealing damage to someone chasing you and constantly staying out of their range. Ashe is exceptional in doing this, as her Frost Shot toggle ability slows her targets she auto-attacks (or Volleys) by 35%, making anyone named Udyr or Skarner cry.

I tried kiting someone, and I keep moving towards them instead of attacking them! Blargh.
Misclicking a lot eh? If it's not in your interest to go balls out and kill someone but to simply do damage or bait, you can attempt to use the "attack move" command (default 'a' key). Your champion will attempt to attack anything in its range, and then move to the location you specified when there are no more targets to attack. By using the "attack move" command, you don't have to wave your mouse everywhere. This isn't the perfect tool for kiting, but it makes kiting a lot safer.

Attack move command sounds very useful!
It has its positive and negatives. For example, if you're chasing someone through the jungle or into a bush, attack moving allows you to get an auto-attack off at the soonest available moment, instead of relying on human perception and reaction. This greatly reduces the chance of your opponents juking you, the AD carry.

On the other hand, if you're trying to chase someone with attack move, and there are enemy creeps following you, your champion will probably attack the creeps instead. Attack move does not prioritize enemy champions, as sometimes you don't actually want to attack the enemy champions.

On the other other hand, you can use attack move to help you CS off of the creep closest to you, instead of having to aim with your mouse.

Cool! Anything else I should know about?
Yes. Take a good look at what items the enemy is buying. Try not to attack enemy champions with Warden's Mail or Randuin's Omen if you can help it; there's a chance that you'll get slowed and your AS debuffed just for simply auto-attacking them. Try not to attack enemy champions with Thornmail, as they counter your lifesteal (the damage from Thornmail can be reduced with MR).

Also, if the enemy team is stacking lots of armor, you'll want to find out exactly how much armor, you'll want to determine which armor penetration/reduction item you want. There's a lot of mathcraft involved. The general idea is that if they have 150 or less armor, Black Cleaver may be worth taking so you can deal tons of damage. However, if they have a couple teammates that excessive amounts of armor of 150 or more, Last Whisper is your friend. Do not stack Last Whisper with flat armor penetration/reduction items if you can help it! For comparison purposes, champions typically have 10-17 base armor at level 1, and 70-85 base armor at level 18.

Ultimately, be responsible for yourself, and don't make your teammates sacrifice themselves unnecessarily for your ass if you get out of position. That's just silly.