Great question! I wish there were more girls like you. I really commend you on your question and taking responsibility for your love life. Most women are out there blaming men for not being initiative enough, instead of asking "how do I become more approachable"... So again, I really commend you on this! You are one very cool girl.
====The answer (how to do it):====
This is gonna sound new-agey and weird... But it actually works... I'm sure you've seen those girls who wherever they go they seem to "glow", and all guys love them and want to talk to them (even though they're average looking, ant nothing special?)... Well, its something you can cause on purpose...
So bare with me, or at least try it. Repeat something in your head like "Wow, you are the hottest person I've ever seen, I really, really, really want to get to know you"...
This is just an example line, but, test out a few, and really feel the line you're saying. Try to "act it out"... And see which one makes you *feel* like the most approachable person in the world.
NEXT: Go up to a mirror, look at yourself, and repeat a few of these lines (once you already feel they make something in you change), and notice how your facial expression changes, notice how your body-language becomes more inviting. Notice how you start glowing and look more approachable.
Btw, this technique works for guys too. I use it and when I enter into a room, all female eyes are on me (and I'm an average lookin dude).