Give him hints that you dont wanna be more than friends. When he tries to talk to you either talk to him in a friend manner without flirting, or ignore him. As for when he looks at you, turn the other way, but not so that it seems like your being rude. Turn away pretending you dont notice and dont look at him for the entire time or it'll get his hopes up.
If he ever confronts you about this be straight up with him and tell him you dont wanna be more than friends with him. But this probably wont happen if you do those two things above.
Hope this helps and good luck!