I like a guy who is confident in himself, has a sense of moral and good manners. Flirting can be done in a decent manner, as long as it doesn't sound like a pick up line e.g.
Good: "If I say you're beautiful will you think I'm a jerk who's coming on to strong?" he says smiling sweetly with his eyes on the girl's face and no where else.
Bad: "You're super fit girl, I so wanna take you out." he says slyly with his eyes everywhere but the girl's face.