Particularly for the rounds before the final, the biggest problem is to get the judges to notice you. Ideally, of course, you do this by dancing so much better than everyone around you that they are forced to notice you. But it also helps to wear clothes that will enhance your dancing and make them look at you.
Red is the best color for ladies' dresses, until you are in a category where costumes are allowed. (Rhinestones and feathers are even more visible than red fabric). For standard/smooth, you want a long, full skirt that will not impede movement and that will move well when you dance. Most of the newcomers don't (yet) have the kind of movement that absolutely requires at least a full-circle skirt, but it should be at least half-circle. Tops can be long or short-sleeved, but shouldn't be so blousy that they hide the arm line, and definitely shouldn't interfere with the gentleman's hold. Makeup is significantly stronger than street makeup, but not as strong as true stage makeup. Long hair should be put up (not touching the shoulders). Jewelry is OK as long as it doesn't move and doesn't break the arm line. That basically means choker necklaces and earrings. Make sure to remove your watch!
For latin, skirts can be shorter and tighter, as long as you can still dance in them. Some competitions may not have time to change, so I would recommend wearing something you can dance both styles in.
For the gentlemen, dark (preferably black) slacks and either a white or black shirt is best. A black turtleneck is also very common. You can wear a long tie if you wear a (black) V-neck sweater or cardigan over it - otherwise it will flap around in a distracting way. Bow ties are generally better for dancing in. Jackets are not a good idea unless they are made for dancing - otherwise the shoulders ride up when you pick up your arms.
For both sexes - it is important to practice dancing together in the clothes you will be wearing for competition. A skirt that seems full when just standing around or even practicing by yourself can interefere with your partner's legs when dancing together. And you want to make sure that it is not so long that you catch your heels in it. Men may find that the shirts whose sleeves are long enough when standing with your arms at your sides become too short when standing in dance position, or that shirts come untucked during the course of a swing. (The simplest solution to the latter is to pin the shirt to your underwear.)
Written by Elizabeth Nugent