How can you tell if someone likes you even if you barely see or talk to them?

they will look at you and when you look at them they will turn there head in another direction straight away. when they are with there friends there friends will giggle and point to you. i liked someone and i found out he liked me because he will start to talk to you even if he/she doesnt normally talk to you. WARNINGS they may just look at you for the sake of looking at you it dusnt meen they like you. they may talk to you mote because they want to be your friend and get to know you more this is rare and if they start talking to you an u dnt even no them it tends to meen the have feelings for you.