All these people are so unhelpful!
Seriously, there's no one piece of advice someone can give you about impressing women. We're complicated creatures, and every lady's different. I personally love smart, nerdy guys who have something to say. But that makes me something of a rarity, I'm told.
I think the #1 thing to remember is that there are many different kinds of people, and you'll have the most success if you try to stick to the women who are compatible with you. Not everyone can date a supermodel, but it is possible to find an attractive woman who likes your personality (which is pretty important).
Before you try impressing the girls, it might be a good idea to make some female friends and just hang out with them. You probably won't get any dates out of this, but it'll help you understand how women think and what they like.
That's my advice. Then again, if I were so great, I wouldn't be single, would I...