Honestly, I wouldn't date a guy that hadn't been my friend prior. My current relationship basically started as a really solid friendship that sorta moved on from there. Talking to a girl is quite simple, you just try to find out what they like, and such, as stated above by
@xpoverzion. From there, you try to see if there's a mutual interest from the other party, and see where things go. And, I mean, Rule #1 is definitely "Don't be a creeper". There's no better way to make a girl run away and never want to talk to you, if you come across as some perv/creep.