How do i start talking to this girl?

[Patrick]

So yesterday my friends and i ended up hanging out with a girl we know and she brought her friend. We had a lot of fun and i got the feeling her friend liked me. I want to try to ask her out, or atleast get to know her better. We've been talking some on facebook but cant get her to continue a full conversation.
What are some general things i could say to get to know her better or allow her to know me better?

[Catherina]

just flat out as her something you want to know about her
ex. you want to know about her family
say, so how many brothers and sisters do you have
sooner or later she'll ask why you're asking her ques and you say you wanna go out with her