Ask More Questions
A good way to impress your date, as well as make her feel at ease, is to ask her questions about herself. Make it your goal to try to listen and ask slightly more questions than you answer questions from her, but don't pointedly avoid talking about yourself. This shows that you're a good listener and that you're interested in getting to know her and hear what she has to say. This also is a good way to take some of the heat off yourself if you tend to feel anxiety during dates.
Generally speaking, try to avoid complaining to your date about much of anything until you've gained a certain degree of rapport. Early encounters tell your date who you are and what to expect of you, and the more negative and unhappy you seem, the more your date may be convinced that this is a very big part of who you are. Especially avoid complaining about exes, or for that matter, talking about past loves at first. One major exception to this rule is if the two of you find something you can mutually complain about, such as a political view opposing one that you share in common, but you still want to take care not to look overly negative.
Come to your first dates with a prepared list -- in your head, not on a page -- of topics that you can feel out and explore with your date. These topics should be interesting but not too controversial or personal. Some good topics include work, hobbies and personal background information, such as where you grew up and went to college or the size of your family. You also can spend time discussing favorites of all kinds, including books, music, movies and TV shows and local hangout spots. If your date asks you to talk about yourself, these are good topics to discuss because they're unlikely to offend, but they can still tell you a lot about the person you're getting to know.
Too Much, Too Soon
Avoid premature expressions of fondness and moving too quickly into emotional intimacy. Even if you're feeling some pretty strong chemistry and you're sure that your date is too, don't rush into things on the first couple of dates. Even if she's feeling the same way, this may scare her off since it displays a poor understanding of boundaries and the proper timeline for a healthy relationship's development. Save those thoughts about how you want to spend your life with him or feel like he's your other half for months or years down the line. For now, just say that you're having a great time with him.