here are some useful openers:
http://ezinearticles.com/?How-to-Talk-t ... id=1426838
It doesn't matter if you start talking bout dogs, its all about your attitude, being interesting and being alpha. sounds pretty easy, but it takes a lot of practice to become good at it. simply start approaching the girls, don't think about the best approach ever or something like this. I guarantee you, if you do this for a while, you won't have any problems approaching all kind of girls. To avoid the best-friend-zone, use NEGs and try to be alpha - you're a the prize, not them (frame of mind: you already have a girlfriend and you don't care how cute the girl in front of you is). Here are some negs:
http://www.scribd.com/doc/4939575/How-t ... ase-a-Girl
Good luck!!