For your photo shoot, you should be sure that your clothes are neat, clean, and free of wrinkles, so they look their best in the photographs. Make sure your clothes are free of stains, lint, and hair for the best results.
The best choice for clothing is solid color clothing with no polka dots, distracting stripes, or prints. Clothing like that can distract the viewer from your face, which should be the most important subject in the photos.
Pastel colors should usually be avoided, because of their tendency to look faded. White and black should also be steered clear of, and you should avoid anything that clashes with your skin tone. Be sure to pick colors that complement your skin tone. If you think you look really good in something that technically breaks these “rules,” bring it for your photographer to look at and make suggestions. Dressing “in character” is completely inappropriate; just be yourself.
You should avoid wearing any distracting jewelry, or anything that might distract the viewer from your face. You should also stay away from “costumes,” since your skill as an actor should allow you to seem like a character without “wearing” that part.