There's this guy that I really like but don't know if he likes me. My friends thinks he flirts with me but I'm not too sure, he usually just talks to me and laughs a lot. We talk a lot in class and we have a lot in common but, I'm just super confused. Can someone tell me how you can find out if a guy likes you?

Simple tell him you like him, and see what he says. I'm a guy and when I was in high school I always wished if there was a way I could know if someone liked me. If a girl told me then I'd know for sure.
However I'm assuming you might be too shy to do that, that's why you're writing here. So if you want to be more subtle about it, after class make up an excuse for him to carry something of yours:, books, laptop, iPod whatever. Most guys like to be useful for girls that they like. Since he's carrying something of yours, he has to walk with you[be certain to walk beside him], you can use this precious time to feel him out. If you're willing to take more of a risk, then when you reach your destination, and he returns your item, be sure to lightly touch his shoulder or upper chest when you thank him for holding it. If you still can't tell. Then see if is still as talkative the next day, if not then he probably isn't interested and vice versa.