Girls

Do they get better later?

If you're asking if they ever stop being two-faced, back-stabbing whores, then no. They don't. In fact, it usually gets worse.

However, girls really aren't that hard to talk to. You're just making a big deal out of it. If you have no romantic/sexual/whatever intentions (which, I fear, you do), it's just like talking to any other person. That's how I did it. Had many a nice chat with girls in my class. Start like that. If you get along well, then maybe you can try inching it closer to being a relationship.

If a girl is constantly trying to be with you or get your attention, etc, then that's probably a pretty good clue that she's interested in you. Otherwise, no, there is no way to tell. Girls are evil and will try to confuse you. Don't fall victim. It's best to assume they all hate you. It's safer.

I know you're thinking it would be nice to have a girl to spend time with, but you don't need one. Stop thinking that you do. If it happens, it happens. If it doesn't, it doesn't. Don't stress yourself out if you never find someone in high school.