I USED THIS AS A FRESHMAN AND ENDED UP DATING THE CHICK FOR 2 YEARS!
if you have a class with her,get her number from one of your friends, or facebook chat her"hey, sorry to bother you, im in your __ period class but i was wondering if we had any homework tonight" from there shell prolly say something like "yea page 34 problems 4-69 odd" or something like that and from there say "aright thanks, that class is so _____ (pointless, hard, easy, dumb what ever floats your boat)from this point go with the flow, ask her what other classes she has or something just make small talk and eventually talk in school