"Thank you for the nice compliment!" is a good neutral response. It depends on the context.
If the guy is not being genuine, like if he's always trying to show you attention and you have already made it clear several times that you don't want it, it's OK to suggest, "That's a nice compliment, but I'm sorry, your attention bothers me".
Now of course, if he is being genuine and you are attracted to him, "Thanks" is probably just a starting point. You probably would compliment something about him as an ice breaker to further conversation.
you say something back if it is not inaporitye back to him or her
How about thank you.
we can have a threesome
say no
dont say anything hug him back
Say hi back!
The guy might like love you back but he might be two scared to say anything or maybe he doesn't love you back but if he ignores you then ask a friend.
i just dont say nything back or k/kk
My girlfriend. Back away.
I know, that's why I had to settle for you..
What you say is I really like you only as a friend. That he's a great guy and all but it isnt meant to be.
He would say, "What??"