Leave your short-shorts and tube tops at home. I personally don’t think it’s appropriate to wear anything excessively revealing on a date–especially a first date. So I like to wear an outfit that is cute, but very stylish. A lower neckline is fine, but nothing with a plunge. Who wants a possible relationship to start out with someone staring at your boobs rather than listening to what you say?
My standard is jeans or a jean skirt with layered tanktops or a nice plain shirt. An interesting piece of jewelry like a necklace can also provide a conversation topic sometimes. Earrings always make me feel more dressed up, but I won’t pair funky earrings with a bigger necklace.
I think feeling comfortable in your clothing is important, too. If you’re constantly tugging something up or down, or having to make sure it’s covering you up, you’ll be distracted from the topic at hand–getting to know someone.
Just my two cents.