Don't be a fake
Don't alter you personality
to pick someone up, like I read in some woman's magazine
Don't be a sheep
If you're out-going, act out-going.
If you're the shy/quite/innocent type. Be that way.
Forget what you know about guys. Not all of them like beer and rugby. And also, not all of them like Perl and Star Wars.
This can be applied to how to impress a woman as well.
For more specific woman things (IMHO):