How he looks at you,not in a creepy way stay away from those,he will be a kind friend to you, like you for who you really are and above all he will be honest nicely and and you need to know for sure that you can trust him or not and and he will know as well as you how special and unique you both are, and his body language, how close is he seeing he can get.
Some guys are more obvious than others. But some sings are if he always finds an exuse to touch you. If he touches your hair alot, or if your walking down a school hallway together and he walks really close to you. And if he's extremely nice to you. If someone is mean to you around them they will probably stand up for you. And they might give you lots of compliments if they are brave enough. And a big one is if he tries to make you laugh. If he cracks alot of jokes around you, almost like he's tryin to Impress you, it's almost a sure sign he likes you.