That's a common one - just had somebody asking about that in comments the other day. A lot of it's fundamentals - the higher the base attraction you get, the faster and more reliably women hook. There's a small "book excerpts" post up on it here:
Book Excerpts: Reaching the Hook Point with Girls
Aside from that though, since it seems like there's a good deal of interest in the topic, let me see what I can cook up in terms of a post on this. It's a frustrating place to be at with your game, I realize... had me boggled for a few years, actually.
Well, keep your eyes peeled for that one!