Men are simple creatures

The following compliments are perhaps more suited towards women.

"Your hairstyle looks great on you. It suits your face shape and body. Where did you get your hair cut?"

"You seem to be a responsible, hardworking, and kind man. I’m sure there are women who appreciate these qualities in you."

To compliment men without flirting, just say something simple.

""Your hairstyle looks good"

"You are a responsible and hardworking man"