Ever heard of Facebook? Just add her as a friend and the next time she's online, all you've got to do is message her saying, "hey." If she replies, talk to her as you would a friend. Don't try to hit on her or anything weird like that, just try to get to know her a bit without becoming intrucive. Once you've talked (or I guess in this case, chatted) with her for an hour or so, ask if she wants to hang out some time.
& if she doesn't have Facebook, you can always get her number (so that you can do the same via texting) by using, what I like to call: The I-Missed-Some-Homework Move. What you do is tell her that you're going to miss a class/day at school for any reason, and if she can text you tomorrow with what you missed in class. Chances are, if she's a nice girl, she'll have no problem and you'll just have to write your number down for her.
It's that easy. Good luck, bud.
