Just remember that chivalry isn't dead, smiling helps, and if you're nervous, she's nervous. So... Don't be nervous. *shrugs* First dates are about showing her the kind of guy you are, and so you gotta just be you.
I've never been on a date myself, but I figure a lot of people kind of get flustered and mess up on a first date. It probably just takes time to get adjusted and if you're feeling nervous or make a bad impression, just tell a joke, or start a friendly conversation. I don't know much about dating so sorry I'm not much of a help. :/
