How do you know when a guy likes you
When he makes an effort to be around you. He talks alot to you. Compliments. He grabs some of your stuff (pencils, pens, useless/worthless things etc) without asking. Catch him staring at you. He tries to nonchalantly impress you. Gifts.
When he smiles at you a lot.
When you catch him looking at you a lot.