You can tell most of the time if he doesnt spend much time with you because he has "other plans" or maybe you find alot of things that make you think he doesnt really like you.
Simple, the guy gets more touchy-feely and more attracted to you very quickly.
You should ask him if he has a GF or try leading a conversation into it.
You ask the guy.
You just know.
If you don't know you like a guy, it means that you just don't like him or you just friends. If you like him you should know.
He likes you. No guy just wants to get to know random girls.
You'll just know.
Just ask
Maybe that guy likes you, and they know about it and are just snickering. Or maybe they just like you.
Then, just tell him so. It is so much better than leading him on.
You just know. Things that you do tell you and sometimes tells him
I dont know excactly but i have guy friends over a lot but if he comes over just to be with you alone, then he probably likes you. If you dont know just ask him. :-)