How do I respond?
I ignore him.
When a guy says, "Hello, Beautiful" I know he is after something other than my personality, because he doesn't even know me.
Get to know me. Go on facebook and check out my timeline. Start a conversation about something I posted in one of my groups. And be sincere about it. Don't just ask a question to get a response. Not happening. You have to peak MY interest.
"Hello Beautiful" is way over-used and just hits me wrong in the beginning. Too familiar.
After you get to know me well, THEN I'll be flattered if you still call me "Beautiful".