put a smile on your face and be a gentleman and when you talk DONT TALK ABOUT HAVING SEX and really be nice ask her if she needs anything hang out with her a lot if she looks lonely go and comfort her make her feel like she is the best thing ever
Depends on how long you have known her. She's probably not going to be rude to you if she's nice. If you have known her a while, then just talk to her like you would any other friend you have and keep in mind her personality. But since you're asking how to talk to her, I'm going to assume that you don't know her very well. If she's a new person, then just keep a cool head and relax. No woman wants a man to look at her and be too nervous to talk. It makes them feel insecure and unsure of whether they're suitable for dating.
You'll never know which ones are nice until you talk to them! Just because they look like they are having fun with others doesn't mean they'll be nice to you... Sorry, but that's a hard fact! So talk to EVERY girl you come into contact with... You never know when Cupid's arrow will strike!