Most Helpful Girl
Take some deep breathes first and remind yourself that it is just ONE girl... if she turns you down or whatever, there are millions, no billions!!, of other girls out there to try and approach. You'll never have to see them again, so take a risk, take a chance, and then move on if need be :)
And here's a great ice-breaker that I personally love...
"Excuse me miss, do you know how much a polar bear weighs? Enough to break the ice hi my name is _______."
It's not creepy, it's not sexual, it's funny and genuine. Goodluck!