First off, regardless of what your heart tells you or how your mind forces you to think, DO NOT obsess with a guy you can never have. There are so many more fish in the sea, so many more guys you can love who actually deserve your love. Do not ever hurt yourself for some guy who will never learn to appreciate you. The signs are the following:
If you are his candidate for a Booty Call and then he doesn't know you during the day.
If he uses you.
If he abuses you.
If he hurts you. For instance, he calls you Fat. He doesn't tease you playfully, he downright treats you like garbage.
If he talks behind your back about you. If he starts rumours about you,
Understand this, guys can really be evil sometimes. Move on if you answered yes to any of the above.
Now that we've got that out of the way, here comes the juicy part. How can you tell if a guy likes you? You like him. You feel it in the gut he likes you back. But you need some substantial proof. I will not go into the types of guys out there, because in the end, there will always be a group of guys who have no niche to fall into. These tips are not foolproof, since human nature is always fickle. So, I suggest you read this and use it as a reference and not your bible.
Ask him. He says he likes you. Case closed. You are done. But, fearing rejection, can you even do that? If only things were so simple. I'll tell you this. Just ask him. This will save you a lot of time. If he says no, then you can understand that he doesn't and may not even after knowing you for a bit of time. Therefore, it will be him who regrets later on when he falls for you in return, granted you guys will hang out and stuff, Maybe not, since if he does reject you, it will be too embarassing, So what you can do is this,
"Do you like me?"
"I knew it! I don't like you either." Haha!
"Do you like me?"
"Yes, as a friend."
"Me too. I was worried because I thought you didn't like me as a friend, " Saved!
If he says he likes you in a way that he likes you likes you and not as friend, then you've just scored yourself your dream guy.
Signs that he likes you
He blushes and sweats. You intimidate him.
He stares at you. (He can be a stalker, beware)
He does things to deliberately gain your attention.
He stutters when he speaks to you.
His pupils dilate when you are up close and you see them, Beware, pupils dilate when it is dim, mostly.
He waits for you. He looks out for you.
He laughs at your jokes when no one else does.
He teases you because he wants you to remember and notice him.
He listens to you and actually remembers little details.
He notices slight changes in your appearance.
He seems sad when you ignore him.
He seems jealous when you are with another guy. Whoo.
His friends all know you when you don't know them.
He smiles back when you smile at him.
He often stares at you and when you catch him, he does that cute head turn, very fast!
He performs sweet acts for you. He defends and protects you. He tolerates you being mean to him.
Signs that he is a player
He is a smooth talker. He is very comfortable around you.
He places his hands on you with ease.
Every other girl likes him.
Just be careful.
There are many more signs, but anyway, just go with your heart, take care of yourself, and let things happen naturally. If it's meant to be, it's meant to be.