Answer:
Be confident. Practice talking in front of a mirror. When you're at the dance just go along with everyone else. Oh, and don't kiss her until you see these actions:
Slow music
The girl is holding you tight and/or putting her head on your shoulder (while you are slow dancing)
She gazes into your eyes with a smile and leans closer. (if this is your first kiss, here are kissing tips: DON'T stick out your tongue, close your eyes 'cause it's impolite to stare while kissing, and make sure your mouth isn't stinky and slobbery at the moment) FYI if you want to tell the difference in her leaning to kiss or leaning to whisper something, if she closes her eyes, leans, and puckers, that's a kiss. If it's to tell you something, she will say something, with her eyes still open, and probably stop dancing if you were dancing.
Sorry. My response is a little long.