Find something interesting to talk about, or just ask her a bunch of (*interesting*) questions (not non-sequitors, she'll pick up on that and think you're stupid).
Also, it turns out that people usually don't care what you say, only how much you say - if you talk a lot and can keep a conversation going and be in the spotlight for a while, you look cool, even if you're not really talking about anything too interesting. Trust me, it's how I pick up chicks all the time, I just go on about something random and just the mere fact that I'm talking makes them think I'm really cool and interesting.