How do I tell if a flirty/outgoing girl is interested?

[Crispy12]

How do you tell if a girl who is generally kind of flirty and outgoing is interested in you? Are there any fairly reliable signs that a girl likes you (aside from obvious stuff like coming up and making out with you)?

There is a girl I like who is like that. A couple of times before she would ask why I didn't come to a couple of parties that were at her house that I didn't know about and suggest that maybe we could watch a show that I liked sometime. There was a guy who I was sort of friends with who liked her at the time so I didn't bite. For a while I didn't see her much, but now we've started talking a little. She went to a formal with me, but we're in college so it doesn't necessarily mean anything. Anyway I've always wondered if there was a better way to tell if flirty/outgoing girls are interested or not. I'm generally attracted to the cute and outgoing girls, so it's usually kind of difficult for me to tell. I am considering making a move, but wanted to see if I can get a better feel for her because I don't want to make an ass of myself. She knows a lot of my friends, and I'd prefer to not make things weird if you know what I mean.

[Gigabitch]

Get others to flirt with her and see if she treats them any differently.