Going out for coffee has gotten me the best results. You just go out, grab something to drink (hot chocolate, if you can't handle coffee), sit down and talk with her. Make sure you pay for her drink, too. Otherwise, I'd suggest dinner. I definitely wouldn't suggest a movie for the first date, considering you don't get to talk much. Since relationships are all built on communication, and you don't talk when watching a movie, it's not the best call.
Just sit her down somewhere, enjoy a meal or a coffee or whatever, go for a walk, and talk to her. Get to know her better. It's a quick way to show that you are interested, and also to get to know her better, which is always a good thing.