I act familiar, I make them laugh (often in the way that the response is: "Oh my God you're bad"), I am also the guy who touches you. They may cut it right away and often show you the road, but if there is a chance, I am already past square one (I have touched her hair and arm in the first minutes). I don't put visible importance into it. I act as if I have known them for years.
See, first look might be important, but while I am not bad looking I don't pretend to win someone over just by exchanging looks. There is always a guy next to me who is taller and better looking. I need to be close, I need her to lend me an ear.
Of course, I am the gentleman. Holding doors, allowing them to go first, offering help etc. These are things that come natural to me, with a smile, charming. I often get the bs "you European guys are gentlemen." (not sure on this though - it could be a stupid cliche)
One thing I have to add and that deserves attention is that a good start, is important, but it is just that. I used to screw it up later, when I had almost guaranteed the deal. Distraction, wrong direction of the conversation, leaning on her to blow a loud fart (OK not this one, but it could be a funny way to lose her)...
Have you noticed sometimes that her eyes are not shining anymore, you feel she's loosing interest, you lost her at some point. Sometimes it is just an impression. You still have her, but it threatens your self-confidence, which is very very important (without being a pompous ass, self-confidence is key).
I believe I have always had the best results when I took the whole matter lightly. If you see it as if you have nothing to lose, it helps you come across much confident and attractive.
Now if you've not gotten laid for sometime, if you feel suddenly desperate to have it, chances are you are more prone to scare her away. But this should be common sense. As in everything else.
Finally, I believe that the ability to seduce women is part of the same talent and potential to seduce people in general. Not to have sex, but somehow to be likable, to make them want to socialize with you, make them become intimate, lower their barriers, share secrets with you and feel comfortable. Always avoiding the "nice guy" status of course that Thorn very rightly mentioned.