Well first of all my dude, you got to stop caring about the outcome, which in your case, is getting laid. If you go in there thinking about outcome, girls are going to know you want something from them and the set probably isn't going to go well, just because of the state you're going to be in. I had the same problem with girls recently and what I'm going to try to do is just go into sets having fun with the girls. I mean, that's what everything should be about, fun. And lol don't worry 2-3 monthes isn't long at all, you still got a ways to go bro. I myself started hardcore approaching about 10 monthes ago and I just recently got my first number, so don't sweat it. But my advice for improving fast? Well there's really no way to improve overnight, but if you want to improve really fast, try just approaching tons of sets whenever you go out. Most guys wouldn't be able to do that, but just approaching tons of sets when you go out, should help you progress fast.
For routines and stuff, look up Mystery Method related stuff. But if you want to know WHY all the routines and stuff work and really want to get deep into why seduction works, look up RSD, which is what I do. Basically RSD is more about what you're sub communicating to the girl, rather than what you're actually saying.