Social Dance Etiquette

Line of Dance
In dances that travel around the room, the line of dance is a one-way street counter clockwise around the outer edge of the room.  The slow lane is on the inside.  More experienced people will be whizzing around the outer edges of the floor. 
Traveling vs. Stationary dances
If you are doing a dance that does not travel (swing dances or line dances, etc.), or if you need to pull over to regroup and start over, move toward the center of the room, leaving room for those that are traveling to go around the outer edge. 
Ask them to dance
One of the best ways to improve your dancing is to dance with more experienced people.  Most people remember what it was like to start out and respect how hard it is to ask people do dance, especially when you are just starting out. 
Say you’re Sorry
Obviously, try to avoid hitting the furniture or other couples on the floor, but should you happen to run into another couple, say you're sorry. If someone runs into you, say you are sorry. When people collide on the floor, it is often difficult, if not impossible, to tell who is at fault.  It is polite to check to see that everyone is okay, apologize, and then get back to dancing. 
Big Finish
Give your partner an underarm turn when finishing a dance.  In that, you are acknowledging your partner, the song and the dance.
Say Thank you
It is always nice to thank your partner after a dance. 
Also, if you asked them to dance, take your partner generally back to where you got them.  I.e. don’t ditch them in the middle of the floor when the song ends.
Follower’s tip
If the leader is off the beat, try to dance with the leader on their beat. 
No aerials on the social dance floor
Aerials and lifts, etc, where both feet come off the floor are dangerous to do on the social dance floor.  Those are best done in performances or circle jams after much practice.