I was just like that in Primary School, but when I went into secondary, it all kind of changed.
Firstly, you have to know your place within the school, now not in a bad way, don't let yourself be pushed around or anything, I mean, where you belong.
Join in with the people that have similar interests, people that you can talk to about something interesting, and you'll be fine.
Oh, and don't ask for girls to go out with you, if they want to they'll ask, my GF's friend asked me to go out with her, so I din't have any troubles with that.