How can you tell if a girl likes you without her ever speaking to you?

Question

How can you tell if a girl likes you without her ever speaking to you?

Answer 1

There is only one way to tell.  If she looks at you and you look back at her and she holds your gaze for more than a few seconds, then she likes you.

Other than that, it's pretty much impossible to tell.

Have you considered speaking to her?  Nothing ventured, nothing gained!