Don't know how to flirt

Okay, so 3 years ago I lost 120 lbs and I'm in shape now.. I've been overweight all my life and never learned how to flirt. Every time a guy makes eye contact I always look down or look away, not that they're bad looking! Most of the time they're pretty cute. I don't do so in a snobby way where he thinks I'm not interested, but more of a "accidental eye contact"... Sometimes they even smile, that's where I come up with a cheesy grin..Any tips on flirting with gay guys? I can hold a conversation once I know he's interested.