Guys only! Help :D please?

ok so i like this guy and i wanna know if he likes me. we have 1 cl together and i sit next to him. hes always joking with me and smiling at me. Like he wen to go sharpen his pencil and i looked up as he was walking back and he smiled and me and i smiled back. During SSR (mandatory reading) ill be talking to my friends cause my teacher doesnt care and the guy is always looking up and me then goes back to doing his work. Guys can you tell me what are some signs you like a girl?