Alright, I like this guy in my class and i don't know if he likes me. How could I find out if he likes me.

Uhm, ask him.
Get to know him a little better.
Or do the ever popular "Get your friend to go ask for you"
I'd suggest the first one.

i've known him for almost a year and he's a senior and i'm a junior also. plus i'm a little scared, what about writting him a note and give it to him.

Sure the old way..'Crush note'...Just tell him the truth and ask him if he likes you..End of story.

- borrow money from him and in the next find him and give them back
- drop sth just in front of him (If he doesn't pick it up, it means that he isn't a gentelman)

and after that try to start talking

But i'm not sure if he has a girlfriend already cause i see this one girl around him sometimes but i think he said she was his cousin but i'm not sure.

Well first off i'd find out if that's his girl friend or not, to save you from a potentially very embarassing situation.

Is she like brain damaged or something?...Like wtf...Puh Lease...Its like you are asking do I have to dial 911 to call 911..

Some here have already given you solid advice on the matter. Njord hates that humans have no direct attitude towards anything in life, choosing to circumvent most matters or accomplish their goals through others. Ridiculous.

Ask him if he has a girlfriend, if so, then move on. If not, then ask him if he wants to go out sometime.