I call it Antipode; here's the theory.
Girls of a certain type hate girls of another type--they are very catty in this way. As it turns out, girls of type "X" dislike girls of the opposite type "Y". Dislike isn't strong enough, they resent them.
What I do, is I play off of this, by suggest that I'm getting bored/disinterested with type "Y" girls (throw in something demonstrating pre-selection here), and that I admire "X" qualities (baiting her to qualify herself). This can make the girl think she is going to steal a guy from the group of girls she hates most.

Examples of antipodes are. Most of these work both ways
Cheerleader/popular----Nerdy, intellectual girls
Trendy/superficial----Hippieish, artsy, eccentric girls
Girls in Sorority A ---- Girls in Sorority B (which hates sorority A)
Mature ambitious highschool girl ----youthful, immature highschool girl
Democrat----Republican (Talking about politics is fine, as long as you're agreeing with the girl, and talking about her emotions too)
Prudish girl----hedonistic prudish girl
Girls that play actual sports----Cheerleders that claim Cheerleading is a sport//girly girls
Business-minded girls----hippie chicks, ultra liberal anti-capitalist chicks
Asian girls---and any non-asian girls, or another asian girl from another asian country. (Anicdotally, I've found that asian girls can be quite condesending towards other nationalities/ethicisities)
Older girls---younger girls
Chubbier girls----anorexic girls
I think this works regionally too--if I travel to Europe, I'm so using "tired of American girls"
WF