The only way to get in the 'friends'-zone' is by giving the impression you want to be friends, or she doesn't like you in that way. If she likes you back, make it clear. Just make it real clear, without saying it, then after lots of flirting, just go ahead and say it. If she says she likes you back, be all romantic and hold her face, swoop in for the kiss and you are gold. If you can't keep it up from here then your ability to socially interact is retarded and learning this becomes paramount to you. Be nice when you need to, but don't seem dependant. Be nice when you don't need to, too, it makes them love you.