lol couple of weeks to break the ice? why dont you just sit down next to her and first thing you say is "im going to cheat off of you this semester" and smile. ice broken. ask for her name, make convo, maybe in a couple of days get her number. also, if youre going up to random girls, what i found works is if you basically go
you: hi, youre really cute and i had to come over to you and say hi. do you know what speed dating is?
her: yes
you: name a bunch of things you like and try to be funny about it. then tell her its her turn
her: if she freezes up and is like i dunno what to say, ask her things about her or something
just have fun with it man, be confident and take initiative and after a couple minutes of conversation, ask her for her number. you probably wont get every girl you try, but more often than not girls like it when guys come up to them randomly because so few guys actually have the balls to do it.