Mate, if you open the way you do and they stick around and are curious about you and want to talk to you, you have the attraction. You just maintain it by being congruent with your opener by staying confident, sure of yourself, open and honest about your intentions and what not. It would be my guess that your real issue is that you're not leading the interaction enough down the right path where sex happens. In other words, it would be my guess you're not pulling because you're either not trying to pull, you're not planning the pull enough (logistics aren't good, not thinking about the end game) OR perhaps after the opener you are playing it too safe, not turning her on or being sexual. Obviously you don't have to finger her or anything, but she has to be able to imagine you as a guy that's going to fuck her that night.
I hope I was clear enough to understand, I am a bit tired
