HAhaha!
I also use this method, but sometimes I forget to not use self depreciating jokes about myself to make them laugh. And don't forget to just act like they deserve to be talking to you, as though your time is too precious to waste around them. This theory was presented in the game I think as to not convey interest in your 'target', and to put the focus on the more plain friend.
Anyway, I'm at uni, so when I get home I'll contribute more to this topic, as I am fairly well versed in some of the theory involved in this, and can cite specific examples of when things have worked/not worked.