Like it's been said. Just don't overthink it. Confidence helps a lot, but you can't just make yourself confident overnight, it comes with time after you've been trying. If that fails, just ask if they want to get high. If she's a stoner or even just likes to have a toke once in awhile, she will probably be down. Who says no to free drugs? When I was in the business in dealing with unmentionables, I had girls throwing themselves at me. 9/10 times they were chicks people wouldn't really expect, and I had all my mates asking me how I'm doing it, all I would say is "being sober sucks"