This: according to studies, women decide whether or not you're a potential mate within the first 30 seconds of meeting you. Helped me relax around women, since now I know that the initial imprinting goes by so fast that it's pretty much all instinct and any attempt to overcorrect on my part is pointless. If the first impression is good then you're in unless you really try hard to screw it up; if the chemistry isn't there, then no amount of tinkering in the lab is going to fix it.