Grammar Help

Hi Grammar Nazis. I just want to ask a few quick questions with some grammar trouble I've been facing lately.

My question somewhat has to do with writing style. I've been having trouble controlling sentence length and as a result I've noticed a lot of comma splices in my writing lately or just a feeling that my sentences are too long/short? I realize that comma splices are acceptable under certain conditions, but I am just not sure when I should be using commas, semi-colons, and coordinating conjunctions only or is it just a matter of personal preference?

A semi-colon can be used to separate two independent clauses, but when do I use it? Should I use a period instead? I just don't want my writing to be comprised of just short sentences, haha. What kind of difference in interpretation would there be in the following sentences, if any?

-John went to the store, I decided to clean up the house. (Comma splice here, but could this be acceptable as a writing style?)
-John went to the store. I decided to clean up the house.
-John went to the store; I decided to clean up the house.

If I had to choose between the three, which one should I be using?

Another question I have is when do I need to use a comma before a coordinating conjunction and when is a comma not necessary? For example, take a look at the following:

-John went to the store, so I decided to clean up the house.
-John went to the store so I decided to clean up the house.

Both sentences seem correct, but are any of them grammatically incorrect?

Thanks for the help, should anybody decide to help me. (See! Does the comma even begin there? I'm getting paranoid.) English is one of my weakest points so any help would be awesome

I don't know whether to simply post a hyperlink or quote everything here, so I'll do both.

For question 1, I suppose this page answers it.
http://www.informatics.sussex.ac.uk/depa...0000000000

Joining two complete sentences with a comma in this way is one of the commonest of all punctuation errors, but one of the easiest to avoid if you pay a little attention to what you're writing. Either you must follow the comma with one of the connecting words listed above, or you must replace the comma with a semicolon.

Question 2 is on the same page, I assume. I just can't find anything specifically stated about whether or not to use one.

Note: I hold no responsibility for its accuracy, it's another internet source (and a UK one at that) so yeah.

If I were to speculate (since I was not properly education on this subject), I would assume that a full stop signals a stop --that is, the end of the idea-- while a comma and a semicolon signify otherwise, and differ from each other only by grammatical use: Commas cannot precede certain connecting words; Semicolons jump in to play comma's role while being pretty.

Thanks for that! It cleared a few things up but brought up more questions!

What you quoted there says that comma splices aren't allowed, right? Two independent sentences can't be joined by a comma?

Also from what I'm getting from that website, it doesn't matter if the comma is there before a coordinating conjunction (for, and, nor, but, or, yet) and a semi-colon must be used for subordinating conjunctions? The exception applies for phrases, where a pause may need to be emphasized?

But why can the word while be preceded by a comma? It's a subordinating conjunction.

I hate English

What you quoted there says that comma splices aren't allowed, right? Two independent sentences can't be joined by a comma?

Also from what I'm getting from that website, it doesn't matter if the comma is there before a coordinating conjunction (for, and, nor, but, or, yet) and a semi-colon must be used for subordinating conjunctions?

From what I read:
1/ Two independent clauses can be joined by a comma with the addition of a coordinator, and I'm trying to demonstrate that in this sentence.
2/ I think you misread something.

The joining comma is only slightly different from the listing comma. It is used to join two complete sentences into a single sentence, and it must be followed by a suitable connecting word. The connecting words which can be used in this way are and, or, but, while and yet. Here are some examples:

Translates to what I said on 1/
If that condition is not met, switch to using a semicolon.

So it all comes down to diction and the syntax is dependent on that?

Would ,and and ; imply the same thing; although, in this particular case due to the context a semi-colon can't be used?

I'm just unsure if anything I write these days is grammatically correct including the above sentences (and this one).

So it all comes down to diction and the syntax is dependent on that?

Would ,and and ; imply the same thing; although, in this particular case due to the context a semi-colon can't be used?

I'm just unsure if anything I write these days is grammatically correct including the above sentences (and this one).

This is something my English teacher told me: A semicolon can be used to join two short sentences that would have otherwise been separated by a period. Perhaps you could use this as a benchmark to decide when to use a semicolon.

This is something my English teacher told me: A semicolon can be used to join two short sentences that would have otherwise been separated by a period. Perhaps you could use this as a benchmark to decide when to use a semicolon.

Yea that sounds right. You should only use a semi-colon if you know what you're doing. The only time I use it [and was permitted to in ap english otherwise points would be taken off] is when using it with words such as

however
nevertheless
rather
furthermore

etc..

So the sentence structure is either

A) John went to the store. However, it was closed

B) John went to the store; however, it was closed.

Hm, I think I got the part with the subordinating conjunction.

I'd like to know what effect a semi-colon has in the message when replacing a period if any. Why would you choose one over the other?

http://theoatmeal.com/comics/semicolon

I actually use the grammar pack for English assignments.