Without going too much into psychology, I'd say your problem is internal. Specifically an inadequacy problem. You need to seduce yourself right now. Get yourself comfortable with the idea that you can get any woman you want. Stop sayingyou cant, stop thinking you can't. The things we tell ourselves have a lot more power then we tend to give them credit for. Think and speak toward things that you want in yourself as if they've already come to fruition rather than dwelling on your shortcomings or things you don't want. "Keep pretending you are what you want to be and sooner or later it'll no longer be an act" that's a quote from a coach of mine in high school that I've always found useful. I hope this helps.

Your right. Its easier said than done. Look at it more as is easier to say than to accomplish the end result. Its easy to speak to yourself positively. Think of what you desire more than what you don't desire. Its that simple but if your looking for a quick fix to the problem then you'll become accustomed to the "easier said than done" way of operating. When you say you find out they are a flirt you mean they're only leading you on and they aren't interested? Maybe you need to examine the way you go about furthering things once you get the initial interest. Since I don't know what you do that causes you to get flaky responses I'll give you a bit of general advice. Lead the woman. Don't ask her questions about what she wants. She wants to be led. Seduction happens between the things that are said. Solidarity and safety will kill seduction.