How do I know?

How do I know if my crush is having a crush on me too?
We smile a lot when we ran into each other,but only if I smiled to him first...and he wouldnt talk to me unless I started a conversation with him..
Please..,is there any helpful tips to know that he is having a crush on me too..is there any way to know?(except asking him in personal..)..I realy have this major crush on him and I realy wanted to know about how he felt for me..please..

maybe he is shy .
maybe he never has nothing to say.

in time you will know if he feels the same way about you as you feel about him. just wait