Politeness is the lubricant that makes social interaction go smoothly. For a night of dancing, or especially if you go back to the same place to dance more than once, a little civility goes a long way.
The Golden Rule
This should be pretty obvious. Behave the way you would like others to behave. Or to put it in a more selfish light, behave so that people would like to dance with you (again). The evidence that you are doing things right is that people are willing to dance with you more than once.
Before you arrive
A partner who is clean, well-groomed, with fresh breath, is in our experience much preferred to the alternatives. Think of the preparations for a date you want to impress, and you will be in the right frame of mind.
Avoid foods which may negatively affect the freshness of your breath (e.g., garlic, raw onions)
Go easy on the perfume, cologne, or after-shave
Taste in clothing style is personal. Some aspects are very practical, however. You may work up a sweat, and you will be touching, and be touched, by others.
If you sweat a lot, multiple layers, and a change of tops, can mitigate the impact of sweat.
Gentlemen, please wear a shirt with sleeves.
Ladies, if you sweat when you dance, a garment that covers your shoulder blade might be a good choice. (Your partner's hand will be on your shoulder blade for a lot of dances.)
Synthetics are a good choice, as they dry very quickly when you take a break
Your jewelry enhances your appearance, don't let it interfere with your dancing, though.
No pointy jewelry on the wrists.
No necklaces that can fly up and hit someone when you do a turn
No hair jewelry that can fly out when you turn quickly
When the music starts
Invitations to dance, accepting and declining
Everyone wants to feel they are special, no one likes rejection, and nobody wants to be the second or third choice. The way you treat others will be there for everyone on the dance floor to see and hear. Everyone wants to receive respect and consideration.
Just as you may have been taught by your parents or in kindergarten, it makes a person feel better when they are asked nicely.
Gentlemen, this means you walk up to the lady and ask her, don't just wave her over from across the room.
Don't assume that a dance invitation will be accepted.
If your invitation is declined, and your second choice saw you invite and be rejected, they will know they are your second choice. Be discrete.
If you are asked to dance, and choose to decline, please do so politely, and consider their feelings. And in case simple compassion is not motivation enough, consider that they may influence the persons you do want to dance with. If you are declining just for the current song, you might offer to dance a later song.
If you have declined a dance invitation for a song, and then go and dance with someone else during the same song, that has the same effect as a blunt refusal of an invitation.
There is value in being relatively blind to skill level and looks in inviting or accepting an invitation.
They might be a beginner who later becomes a fun dance partner, and will remember when you were nice to them.
Somebody danced with you when you were a beginner, paying it forward is good for everyone.
Treat others as you want to be treated.
Gentlemen, don't walk up to a group of ladies and ask if any one of them wants to dance. Pick one, and ask her. If your first choice declines, you have a situation that calls for some thoughtfulness and delicacy. If you ask another of the ladies in the group, she may feel offended that she was not your first choice. However, if you don't ask, the other ladies may get the impression that you don't consider any of the rest of them worth asking. Either way, you lose.
Ladies, be aware that if you are grouped together, it may make it a bit intimidating for a man who isn't very self-confident. Some men may decide there is too much risk of offending.
If someone asks you to dance a dance you are not familiar with, or comfortable with, you can politely decline on that basis. Or if not decline, at least warn them. If you do decide to dance anyway, setting the level of expectations in this way probably takes a lot of the tension out that might occur between dancers of differing skill levels.
If you don't know the dance, please, don't say that you do when asked to dance. This makes for a very frustrating experience for both partners, and makes you unlikely to be asked to dance by that person again, even for a dance that you do know.
On monopolizing a partner: Sometimes someone will ask you dance many dances consecutively. If that's what you want, great for you. To the would-be monopolizer, please consider that your partner may want to dance with other people. This is where it pays to be very attentive to their reaction to a request for another dance. If it's not an enthusiastic yes, be nice, they may be too nice to just tell you no, and do you really want to dance with someone that is not happy to be dancing with you? And to the person subjected to such attentions, you are within the bounds of polite manners to say you'd like to dance with someone else for the next song. Try to be gentle about the refusal, though. As to the effects of unwelcome monopolization, you may very quickly use up any good will of that person. We have seen a few cases where the victim will run away, and grab anyone else to dance, when they see the would-be monopolizer coming.
Be polite and considerate, in the meantime, use your judgement. It is possible for someone to keep you from dancing with whom you would like, or at all. Sometimes the right thing to do is to just say "No, thank you." Treat others with respect, but do stand up for yourself.
While the song is playing
The most popular dancer on the floor is the one that makes all their partners look good, including the beginners.
Be gracious, accept your partner as they are, don't offer unsolicited advice, instruction, or critical comments.
Followers, please don't back-lead, its effect is a non-verbal criticism of the leader.
Back-leading is where the "follower", usually the woman, tries to maneuver the "leader", usually the man, into doing the pattern she wants the way she wants it.
Leaders, if the follower didn't do what you expected, this means you didn't lead it properly. Leading means communicating to the follower what you intend for her to do. A gentleman takes responsibility for whatever didn't go as planned in a dance. Stick to patterns you can lead her in. To do otherwise is potentially rude and embarrassing to all concerned.
Followers, this may be unfair, but the leader is the leader. If the leader is not in time with the music, follow the leader's timing.
Dips: Leader, do not dip your partner without asking before hand. The same applies to any aerial maneuvers. Your partner may have physical concerns or just plain nervousness about these moves.
Smile: Unless the dance in question has other requirements, look at your partner's face while you are dancing, and smile. If you make dancing with you an enjoyable experience, people will want to dance with you.
Physical closeness: whoever wants to stay furthest apart decides how close you are when you dance. Normally, the gentleman puts his arms into a dance position, and the lady walks in as close as she is comfortable. As your skill level increases, some dances work much better if you are dancing in contact, such as American Smooth, International Standard, and Bolero. Some dances are difficult if you do not dance in contact, such as Quickstep. Dancing in contact means that there is contact between the leader and follower from about the hips to the ribs. If you haven't been taught how to do this properly, you may kick your partner or be kicked. Ladies can use her left hand on the man's shoulder to maintain a separation.
Don't hurt your partner
Don't force a turn that isn't working.
Don't intentionally touch your partner's hair (it may be unavoidable if your partner has long hair and you are doing quick turns.)
No inappropriate contact on the dance floor.
When the song is over
Thank your partner, and make any compliments that your are able to. The gentleman should escort the lady back to where he brought her onto the dance floor.