You aren’t the first person to ask about some mind-body help to prep for passing the bar, and we have some success stories in our archives about precisely that (medical boards, too).
We actually have a lot of materials that could be helpful here. I’d suggest you start with one or two and stick with those until you feel you’ve really absorbed them. Then, if there’s time, move on to a third. But if you find something that seems to hit your sweet spot, just stick with it. If it ain’t broke, no need to fix it.
Okay, so my top choice for this would be Shirley McNeal’s Test Taking Mastery, because it’s very specific to test taking. She focuses on before, during and after the exam, and uses her excellent voice, presence and hypnosis skills to help you enter a state of relaxed concentration and recall. Needless to say, you still have know the content - it’s not a substitute for studying. But it will help you retrieve what you learned.
I also like Emmett Miller’s Winning at Learning for help with staying confident and calm. He also has suggestions for memorizing and anticipating a successful experience.
Martha Howard has a very fine guided meditation for help with concentration and confidence under pressure. It’s called Greater Memory and Learning Skills and it’s another excellent hypnotic journey.
And if you enjoy the nuanced subtlety and oblique suggestions of pure Ericksonian hypnosis, David Illig is your guy. In Improve Your Memory, he mixes his primo technique with hemi-sync musical tones and subliminal suggestions to help you absorb, learn and recall material.
And if you respond well to my stuff, then you might also want to try Self-Confidence & Peak Performance, but it’s more general - doesn’t specifically target test taking.
Remember, there’s no need to overwhelm yourself with all of these. Start with one or two and see how you respond to them. If it feels right, stick with it and don’t bother with the rest.