What are the signs that a guy likes you??

Eye contact reveals that you have his attention for sure. I think that's the first thing. But it won't let you know anything about his intentions. Does he go out of his way to be where he can see or talk to you. If he's not forward, does he interact a lot when you have something to say? Is he listening and picking up on your interests?

It depends on the guy, not all guys have the same "signs"
but there are some universal "signs"

if he gives you physical contact, that's good
so is eye contact and truthful answers

Rather than asking about signs, why don't you better use your time and talk to the guy instead and just ask him if he wants to go with you to grab some coffee.

Its all in the eyes and the key is body language!