I've found when I just imerse myself in my own reality and only occasionaly look around to see whats going on people approach me more often. In other words I act relaxed, laid back, and don't demonstarte that I'm shy or nervous about anything. I'm not drawing attention to myself and I don't act too excited when anyone talks to me.
To add to what your looking for, having people approach me (male or female) seems to increase my value and when I finally do decide to go up to someone of the female persuasion it seems to make them feel special that they've done just enough to attract my attention. Let me add though that I always allow myself to remain neutral and don't telegraph intrest. This way I get to keep the sense of mystery that most women find intriguing.
I've also heard that working your way down the food chain is a another way to demonstrate a higher value. What this consist of is talking to the hottest girl, then the second hottest girl, then the third, and so on. The theory is that when women see you talking with someone that they percieve to be more attractive then them it enhances your value in their eyes. However one of the things that I am constently being told is to make sure that your approach is congruent to your personality and honestly, I base my approach on being low key guy (mysterious not shy. The way I like to describe it is the one thats able to slip under the radar) so I feel that this approach doesn't play to my strengths. Nevertheless your more than welcome to try it out.