What are some little subtle ways to see if a boy likes a girl?

Because I like a boy & my friends have seen him look at me alot & in Spanish today he did twice once wn I walkd 2 my teachers desk infrnt uv the class & wn I wlkd bak & I looked @ him he turnd his head rly quick & once he looked straight @ me wn I was sitting @ my desk & I was looking back @ himthen looked away cuz I was getn red then l8r @ lunch I was talking 2 my bff & he had his head on his hand and was looking & smiling @ me & as soon as my bff glared @ him he got all red & looked away & tht is the 2nd time tht has hpnd & ystrday I was tlkn 2 my teachr and then he wlkd in & it was only the 3 us. Us & he loudly makes tht sound like something is in his throat & I look up at him & he smiles at me hen 2sayy i was leaving a class and when iw as gonna open the door 2 get out he opened it from the other side of the door and we al ost ran in2 each other and he was sweet & let me go while holdn the door thn i smiled and said thnx and he smiled bac..wt does ths mean?