Talking to a girl you are attracted to can be hard. Infact long ago I used to get so nervous at times I felt like crying or fainting. But talking to girls doesn't have to be that hard. I'm no expert, but It's easier if you have a sense of humor, what your saying doesn't have to be extremely funny. When you talk to a girl just try to joke around a bit and keep things on a light note, like you would with a friend. You can always start by commenting on something she is doing. Maybe you can even playfully tease her, not in a rude insulting way. But I know humor is a good start to anything.
Remember having a relationship with a girl isn't just physical stuff, it's not an unlimited supply of intimacy. Alot of the time you guys will just being doing activities together or having conversations. So you should make sure you search for the type of girl who's personality you like. For example I can't stand over aggressive girls, or girls who use too much ebonics. There are lots of mean girls out there, but you shouldn't let their opinion of you phase you. If they are that mean I don't think they are worth your time anyways. That might just be something you hear but time is very important.
Rejection may hurt but no need to be depressed, and don't get too upset. Think about it, Every 2 seconds a guy probably gets turned down somewhere in the world. It's been a while since I talked to a girl. I got rejected lots and lots of times, in the worst possible ways that even put me in danger and almost got me in trouble. But i'm still ok, and right now it's in the past so it doesn't matter. But if you need anymore help feel free to message me. You can always message me situations where you might see a girl and I can give you some pointers one what you could say.