It depends on who smiled first, if he smiles at you the best way to smile back is with your regular smile or in any way that makes you most comfortable. And if you happen to smile first, make sure to look for his reaction.
yes it would you should definetly do this.
it depends if the smile hes giving you is a friendly smile or a flirty smile.
Smile.
smile
The way u can tell a Guy likes ur smile he will look and smile then try to fix his clothes nice
A smile.
Be yourself and smile at him.
when he looks at you and smile
It does not necessarily mean anything - he may not be interested in your smiling.
He doesn't want you to see him smile? Are you sure he was actually holding back a smile? He doesn't want you to know how he feels...why???? that depends on who this guy is to you and many other factors.
If a guy has a crush on you they will smile at you, say jokes... try to be funny, pick on you, flirt... but if the guy is the type that is shy he will smile an look away, his face might turn red, he will stuter, he will be clumsy.... ect.
Just try to smile