How do you know if a guy likes you?

we've nevr said a word to eachother, but he is always starting at me, he does werid things to get my attention, my friends think he likes me, ive caught him several times friends think he likes me, ive caught him several times looking at me, n when I do he smiles somtimes or looks away fast or shyly.its been a yr n now thts been going on. looking at me, n when I do he smiles somtimes or looks away looking at me, n when I do he smiles somtimes or looks away fast or shyly.its been a yr n now thts been going on.