This is a subject about which I’m totally unqualified to render an opinion. I’m perfectly comfortable discussing a man’s trial uniform. A man’s trial proper courtroom attire normally is a dark suit, white or blue shirt, a tie that may have a pattern but not a loud one, brown or black shoes coordinated with the suit and dark (not white) socks. Any accessories must not be distracting to the viewer. This works well for politicians also, and they, like trial lawyers, can only go wrong if they vary from it – see one who did above and who got criticized for doing so.
Although I’m unqualified to discuss women’s wear, that doesn’t mean I can’t pass on advice from others. Quite a bit has been written about women’s courtroom attire and here are some articles on the subject that you can read:
There is even a Law Review on the subject of women’s attire. See Gonzaga University School of Law Volume 45 (2009-2010) Beyond a Reasonable Doubt: One Size Does Not Fit All When It Comes to Courtroom Attire for Women
Hale Starr and Mark McCormick’s Jury Selection 432-433 (3d ed., Aspen 2001) offers a good discussion of proper attire for women trial lawyers.