Here are some issues I encounter among adult skaters:
Undergarments
It's amazing how often I talk about underwear on this blog.
Really make sure you can't see through that white dress. A quality skating dress, in any color, will have an understructure made from a sturdy illusion, with the "fashion" dress constructed over it. If you have a white or light colored dress that you really must wear, but it's see-through, you can have a seamstress add such an under layer (it's complicated but not hard), or get a flesh-colored (whatever color your flesh is) leotard to wear under it. Make sure that the leg openings and the straps of the undergarment are undetectable.
Too short?
Entirely your comfort level. Personally, I think skating dresses on anyone should cover their buttocks; with adults I'd add the word "dignity." My preference is no shorter than just above mid-thigh in front, and at or below mid-thigh in back.
Too long?
For adults, knee-length is not too long, but if you go with a dress this long, make sure the skirt is made of a very light weight fabric like chiffon so that it moves. Adults sometimes skate very slowly. A heavy skirt is just going to sit there, exaggerating the effect. Don't make it longer than knee length in the back, as this can risk catching the blade.
Pants!
Yes please. Pants are very classy on adults, with a light loose shirt that moves when you skate (see above). The shirt can be shorter than your butt cheeks. Make sure the pants are narrow and LONG-- they should hit the floor at your heel when worn barefoot. Make them black. Colored or jeweled stripes down the side seam, or appliqués at the ankle are very nice. Don't wear those Chloe Noell pants with the spiral stripe that all the girls wear.
No real reason, I'm just sick of them.
Sparkles
I live for sparkles. And you really do need some jewels even for testing. Again, it helps with the illusion of movement, and sometimes with adults movement is all about illusion, because we don't move all that fast. However, you don't want to be weighted down like the Virgin Queen.
Gloves
Are you on the Russian World Team? If not, please do not wear gloves for testing or performing. It looks silly. (It looks silly on the Russian World Team, too, but they all do it.)
Boot covers and over-the-boot tights
Boot covers only with pants, and then only in the same color as the pants. Please do not ever wear over-the-boot tights for testing or competition. They do NOT "make your legs look longer." If you're wearing them to disguise your beat up skates, here's a news flash-- you can polish skates with shoe polish.
Modesty
For adults-no backless, no plunging necklines and definitely no cleavage. Anyone with a bounce, if you know what I mean, should look for good supporting undergarments (ones with real support, not those stupid "sports bras" that just mash you flat without really dealing with the bounce problem). Judges really hate bouncing boobs. Remember the word "dignity."
What are your favorite do's and don'ts for adult skating garments?