[This list by Paul Tyler was originally posted on the old usenet feed rec.folk-dancing. You can read the original post and the whole thread, because Google Groups has maintained the old usenet feeds going back to the before times and rec.folk-dancing is still alive and active. — Bill Tomczak]

1. Fit his/her movement to the phrase of the music. Most contra dancers dance at one speed and are as guilty of finishing a figure too early. For example, a good dancer should be able to pace an unembellished ladies change or right & left thru to fit stylishly with the eight beat phrase. Another example is thinking all swings are the same. If in a square the caller says "only once around," then by god, swing only once around. (As you can quess, this happened to me the other night. The beginners did fine, the experienced contra dancers didn't listen. They must have felt they had a right to swing as long as they wanted.)
2. Know how to appropriately embellish. I'll bet you many people who think of themselves as good dancers couldn't get through a dance without all the extra twirls. They don't know what the basic movement is or what it feels like. If you don't understand that, then the embellishments lose some of their character, even their potency. Embellishments and flourishes work when they come at the right time in the right situation with the right dance buddies. They should not be automatic. One simple example is the do-si-do and the now ubiquitous twirls. A good dancer paces it out and gets a feel for the timing before venturing any twirls. Same with the hey, the ladies chain, the grand right & left & others.
3. Good dancers know where a figure is going so they can direct their momentum to the flow of the dance. This is a much bigger challenge in squares. Who/where do you face when you end a swing? Or a do-si-do? How do you break a circle to lead on to the next? Or to form a line? The challenge of flow in contras is more controlled so the dancers, but there are subtle shifts of flow where the dancers have to direct their own energy. Not every gypsy (gag me) or do-si-do or star or circle is the same.
4. Good dancers make better dancers of the people they dance with. Not just their partners. A good dancer helps the people he's in contact with move on to the next figure with ease and grace (see point #3). Gentle pressure clearly tells the person where they're going next. If they didn't know, it will help them figure out the dance. If they did know, they will recognize it as good dancing (see point #3). The good dancer also appropriately teaches dancers he encounters who are lost. This is best done by gentle, but firm shoves and encouraging words. In the heat of the dance, and during the caller's walk through, good dancers don't fill the air with more words. But they still help teach the dance. Sometimes it's just by example. Other times it's by being an active inactive (doing the small complementary moves that help the active dancers; or standing ready to go, pointed in the right direction, with the proper hand ready to extend, and a smiling face looking at the active dancer soon to be engaged).
5. Good manners. Good manners. Good manners. A good dancer listens and walks through the figures with the caller during the walk through, even though he/she has done all this a million times. The good dancer helps beginners see what the caller is trying to do. Also, the good dancer doesn't twirl a lady/gent who clearly isn't ready or willing to twirl. Etc. ect. etc.
6. And one definition by negativity. A good dancer is not self-centered. He/she doesn't lose him/herself in flirtation or twir-a-mania. Contra dancing and square dancing are done in a set. They are not just couple dances. A good dancer dances with awareness of everyone he/she is interacting with in that figure.