You have to change your intent. That's the best way. First, start telling yourself that you're just fine without a woman and you don't need them. Then start telling yourself you desire a women, it's just something you want. Basically change your mindset from needing a woman in your life to just wanting a woman in your life.
I went through the same exact thing you're going through. I'd go out to the clubs and strike out night after night. Then I took a break from women completely. I started going out with the mindset that I didn't need a woman at all, and this was what changed my striking out with women to getting women on just about any given night. Women can tell when you're desperate, and they are instantly turned off by your need for having them.
When you stop needing a woman in your life and start wanting a woman in your life, your body language changes, the words you speak change, and the way you say them changes. When that happens, women take notice. This also helps keep you from having that deflated feeling when you do strike out.
Another thing that will help is to stop worrying about screwing up your chances with women and start looking to see whether they are screwing up their chances with you.