OP, the most important thing you can do on the dance floor is move with a woman.
I'm a great dancer, and I usually dance alone because most men don't know how to dance. If a guy comes up and tries to grind on me, that's not attractive. Or if he starts busting out some hip hop moves, or some footwork, it's not that awesome.
However if I am moving to the beat, in a sensual way, and a guy is able to come up and start moving with me, that is very sexy. I think the sexiest thing a guy ever did was follow me to the dance floor, get behind me as I started to move, and he really just followed me, but in a consuming way, if that makes sense.
The most awkward dance partner I ever had was a professional tango dancer. He only knew how to lead and tango! Sure, doing the tango to "Love Song" by the Cure is sort of hot... sort of. It for sure gets old by the third non tango song.
As far as classes go... they actually will help. you'll learn all kinds of ways to move your body, so once your body is able to identify the beat, and you add in some sensuality, all the things you learned in classes will come out naturally.
