As weird as this may sound... possibly one of the best pieces of advice I recieved... every time I go into largely social situations, I make sure ALL my friends know that if they see someone I should talk to, to repeatedly beat my ass until I do. Works WAY better than you would think it would, because in the reality of the world, there is basically no situation where you can not just have a normal conversation with a girl.... if you are in an obviously social situation, you are being weird if you dont.
The "friend zone" is not as scary as one may think if she is a nice girl that you like hanging out with..... Make your intentions with "other" girls known to her and she will be a very powerful networking tool to "kick your ass" and make you talk to other girls. This also could remove friendzone status after awhile if you really screw with her.... I think there are a few dumb chick movies where a "friend zone guy" gets in with the girl after he starts dating that could prove that concept.... You sorta have to know excatly what you are doing if you want it to work well though.