There's not really a good 'universal icebreaker'... don't force it. If you're having a conversation with her regarding school or whatever, try to smoothly change the topic to something partially relevant or related. If you just come up to her with some random topic out of nowhere, it's going to be obvious how hard you're trying, so just be patient and hopefully something will come up... if conversation doesn't ever end up 'flowing', maybe it's just not meant to be. I've met some pretty hot girls, started talking to them, and realized that it was pointless because there wasn't anything there but a physical attraction. I don't care what anyone else says... without some substance, it'll get old.
Then again, if you're the type of guy who just wants to get laid by a hot chick, completely ignore my advice.
