You might catch him looking at you a lot, he might act shy around you or treat you really extra kindly. He might hug you or say sweet things to you or text you first. Maybe he flirts with you or hints around. You can usually tell. Good luck :)
Agree with @ fashion child and if he hasn't told u just ask..or get him to tell you by hinting it and stuff:)..don't assume or try to figure it out by the way he acts or body language tho..cuz that's not dependable or for sure..get a straight answer!!:)..