As conservative as possible-you can be dismissed, fined, or held in contempt for improper attire. Perhaps, dress as if you’re going to be interviewed for a job.
No T-shirts, or clothing with silkscreen or graphics. No “gang” colors or attire/accessories. No trainers, hats, bandanas, or team jerseys. Your attire should not be a distraction to the interrogation process. No skin-revealing attire; if you have tatoos, they should be covered up as much as possible.
Remember, you’ll have to go through a metal detector and search process, so don’t bring a bunch of stuff (accessories) as you’ll need to pass that through the detectors, which can be cumbersome.
As the other posters have indicated, no flashy jewelry or accessories. Hair, makeup should be toned down, so as not to distract from the hearing of the case. Your character and appearance are scrutinized by the jury even though they’re instructed not to take that into account.