It depends on the girl. some will act shy and smile. Others might try to talk to you alot and laugh alot at funny things you say. If you catch a girl looking at you alot, she might be interested.
when i like a guy a cant keep my eyes off him and then if he catches me i cant help but blush another way you can tell if a girl likes you is if you find her allways talking to you even if it is about nothing at all she will still want to talk to you and hear what you think and if she can remember thing like your fav color or band then she likes u
