I used to use this technique. I'd sit down at a bar next to a georgeous female and say, "Hi. My name's frank. I have the most talented tongue in the contiguous 48 states plus Alaska and Hawaii. Wanna try me out?"
I got slapped 9 out of 10 times. But that 10th time? Whooooooa boy!
Just kidding.
After some nice, friendly conversation, right in the middle of a most interesting part, look suddenly at your watch and say "Oh my God. I'm supposed to be at xyz in ten minutes. Frantically put your stuff in your pockets. Then stop. Look her in the eyes and say. I'd love to finish this conversation. Will you trust me with your phone number?" If she give it to you she's interested. If not, she's not.
However after many checkered years of relationships with women, I say there's no one technique that will work with all women. Just be natural, easy, and hardest of all be yourself. If they like you for what you really are, that's the best compliment they can pay you. (But I always made it a policy of attempting to get that phone number no matter what.)
francois