People actually will show signs of liking in so many different ways! There's no certain signs!
Some get really shy that they can't even talk but some feel comfortable and talk easily! (just like these differences)
But usually
-He won't get angry on you
-He might feel a bit nervous around you
-He will be around you almost everywhere! Or tries to be around you by any excuse
-Some might stare a lot, some people consider it rude but sometimes when someone like another, they get drown deep into person's face and they can't look away!
-He might make compliments a lot, and sometimes those who get nervous become obvious when they lose their words or find misspells and kinda they die until they make a sentence together!!!
ect . . . .