greasymadness
It's a numbers game. Choose a repeatable pattern of analysis and action. It should cost you as little as possible, and give you the best odds of success. It will not work all the time, of course. Nothing can. But over time, it will result in more positive outcomes for you.
In the world of "I'm and American male trying to get laid", the cheapest strategy also happens to be the most likely to bring success. Treat all females like disposable pink tacos. Don't pay for dinner unless you get a blow job first. Don't call them in the morning, ever. Repeat, repeat, repeat. If it seems counterintuitive, that's because it is.
If you are nice to women, they will like you. They will want to be your friend. But if you want them to give it up, you have to treat them like crap. It's all a matter of preference.