Give it time. I know that sounds like a cop-out, but -- like the old song says -- you can't hurry love.
Another thing to keep in mind is how you act around the opposite sex. I knew one fellow who had me beat in every department. He was charming, witty, handsome by all standards...but he couldn't keep a relationship going to save his life. Turns out his major problem was that his idea of how to run a relationship was more like holding someone hostage.
I dunno, man. If you think you're doing everything right, maybe now is the time to start asking people who know you in meatspace what they think you're doing wrong. I don't know you, so I can't even begin to guess...