You want your dance to follow the musical elements, so stay with the rhythm. And even thought the music is starting to feel oh so good, don't get so excited that you start whipping her around like some rag doll. After all she's your partner, not your puppet. Finally, Relax and Have Fun. Remember you are out here to have fun with another person.
Dancing is a social activity.
So relax, enjoy dancing, but be responsible. Dancing, with a few exceptions, does not pay the mortgage, car note, or the rent, so don't take it too seriously. If the lady makes a mistake or you do, don't worry about it. Let it go, apologize, if warranted, and move on. It's no big deal unless you make it a big deal.