How to know if a shy guy likes you?

(this is quite long!)I have many situations with this guy from my school. this first time one of his friend called me over to the table and told me he liked me, he just smiled and looked away. That same day I saw him in the hall way and he just looked down and smiled.One time coming from my adv. piano cl he seemed to want to tell me or ask me something but I sped up the pace because I was nervous. Another time at lunch we were in the same snack line and when he got his drink he kinda fumbled it, and had a hard time getting it.Do you think he may like me? And what should I do??