[This is not included in my book on social dancing, but is offered here as a freebie.]
I compete and perform only occasionally, but have watched hundreds of dance performances and competitions over the years. Here are a few tips on pleasing your audience.
As a performer or competitor, you want to show up clearly on the dance floor. Don't wear all black! Dancers dressed entirely in black tend to disappear, particularly if the background against which they are performing is dark (e.g., wood paneling). For your audience, it's like watching shadows.
Gentlemen, this means that if you are wearing black pants, you should include some light colors in your top (e.g., a white shirt, and perhaps a colorful tie). Ladies, this means that wearing that little black number may not be the best idea for your Latin or Tango performance. (Lack of color is rarely a problem in women's Standard and Smooth dresses, which usually err on the side of gaudiness.)
Performers--and in some events, competitors--get to select the music to which they are dancing. If given the choice, pick wisely! A great song can energize your performance. Conversely, even the best dancing can fall flat if the music is dull.
Try to select a piece that your audience would enjoy as music. Does the song make you want to tap your toes, clap, or sing along? Is it haunting? Does the melody linger? Does it tell a story? Are there vocals? Is it catchy, dramatic, or playful? Would you want to hear this song in concert? If the song is mechanical, saccharine, or was recorded for an elevator, you may wish to reconsider your choice.
I can't stress this enough--since dancing expresses music, it's hard to rise above a bad song! My book, Much Ado About Ballroom Dancing, lists a variety of good songs for each of 16 dances.