Agreeing to help her with ANYTHING. Applies to girls you're meeting for the first time - a lot of guys will be talking to a new girl and she'll say something like, "oh man, I have to get my car fixed" or "I'm new in town and trying to find an agent" (I live in L.A., people), and the guy will come back with something like "oh, well I'm really good with cars, I can take a look at it" or "Well, I have a friend who's an agent, I can see if he'll look at your work." Do this, and she will NOT hook up with you. Why? 'Cause she hasn't had to do anything to earn your help, and in her head she'll be thinking "what a great resource - welp, I can't screw this arrangement up by sleeping with him!"