How do i ask a girl to dance?

im going to a teen club and i need to know how to aska girl to dance ...should i just walk up behind them when they are dancing with their friends and start dancing with them...i tried it before and about 80 percent of the girls danced with me and the others just stopped dancing.How do i ask a girl to dance?
The etiquette is pretty straightforward. You go up (no sneaking up from behind!) and ask, ';Would you like to dance?'; or something similar, short and simple. This should be done between dances and you should not interrupt a conversation, using the same courtesies as anywhere else. The really nice thing for shy guys is that the girls are not allowed to say no unless they have a really pressing reason, at least if they're being at all courteous, so there's no fear of rejection to worry you.How do i ask a girl to dance?
the old ';aw-w-w-w shucks, shy guy, toe of shoe in the dust'; approach is actually charming to most ladies.

and you can always try approaching from the front and asking, ';May I have this dance?'; i don't think anyone will shoot you for it.
you should say Yo fooo, u bettra dance with me. Nah psyche
im a girl and just to say if i knew you well and liked you at least as a friend i would say yes ask her but don't do it in front of her friends becasue girls get self concious if their friends think someones really geeking
May I have this dance?
I personally think it's kinda creepy when I guy sneaks up from behind. Come foward toward her and try to make eye contact. If she sees you and looks away, she probably doesn't want to dance with you or is too shy. If she keeps eye contact, keep heading her way and take her hand. And lead her elsewhere to dance.