Answer:
Well..... just wave to him when you see him and say hi, and when he says hi back just kinda stop him for a min and ask "maybe we should talk or hang out sometime"! if he says no then just say ok because he will think that u r layed off and not all drooly and all over him. so if not then just continue to say hi or hey to him and he will be able to get to know that u r intrested in him!!
Hope this helped!!