Quite often people get zone'd because you're much too nice. This isn't a treat 'em mean thing either. If you behave like a friend from the get-go, then you're going to be treated like a friend. The answer to this is flirting.
when you first meet them, flirt. Not aggresively that'll scare them away do it enough to let them know you're interested, find a subject that you both like and make sure you actually know something about the subject. Intelligence is sexy if you're caught on a subject that you don't know anything about say and ask them to explain it, that is also an attractive aspect in a man.
Biggest tip, you can look at her body after a while, don't oogle her breasts or arse but just look, this can be a deal maker or breaker so only use it after you've been talking a while. Do it descretly at a time where she might notice. If she does notice and likes the fact that that you're showing that you're attracted she'll blush or smile and most likely do the same to you.
Most of all, be yourself and talk to her like you would a normal person... it might take a little practise but eventually you'll learn how to go with the flow of things and once you're feeling comfortable with talking to strangers things will go a lot better, confidence is also attractive.
I've done this before and kicked myself for it, don't forget to take her number or her MSN or something!
