How do you know If a girl likes you?

She'd play with her hair, flirt with eyes, "check" you out, she'd smile a lot and you'd see twinkles in her eyes. The good way to find out is to sit close next to her and if she's not avoiding the closeness, she should like you, well at least I'd pull away if I didn't like the guy in more than a friendly way. But god damn it! ask her ! that will just boost your ego, because you did such a heroic thing! =p

She might be kinda "out of it" or "off" when she's around you or she could flirt a lot or smile a lot, or twirling her hair, biting her lip Not licking it though!

It really depends on what kind of girl you are talking about. If she is shy, she will have a hard time looking at you. Her speech may seem to be impaired at some points. If the girl is flirty, watch out. You never really know with this kind. Some girls are just out in the open, touchy-touchy because they enjoy the reactions they get out of boys, if they know they can get it. Basically, though, you can tell if a girl likes you if she keeps coming around; calls you, texts, you, ims you, goes out of her way to talk to you say at like work, school, wherever. Also look for body language and eye dilation. She may also appear to laugh at almost everything you say, and compliment you on certain things such as your smile how funny you are, how smart you are, or they could be playfully mean and tell you what an ass you are. Anyways, hope I helped.

Well if a girl likes you she may smile then blush and she might act silly only around you an nobody else.

Is she constantly playing with her hair, is she licking her lips, constantly looking at herself in the mirror when your around?