I had one for the same reason you did, because my Stage II check was pretty much FUBAR.
Make sure your uniform is squared away and shoes are shined. You will have five or six board members. Three will be API instructors (who will cast the deciding votes), the others will be flight docs. They will delve into your medical history, look into your motivation to be here, ask questions about family issues, and perhaps throw in a knowledge question or two. All I can say is do not interrupt them, make sure you do not call a female officer "sir" (Trust me, in the stress of a PRB this is not hard to do; I came damn close before I checked myself just in time), and maintain your bearing.
Do not act like an arrogant hot shot. If they ask you a question such as "So why did you come here........to be a Top Gun and ride around in a jet with your hair on fire." The correct response would be: "No sir/ma'am, Maverick would have had his wings taken away or at least been FENAEBed for the stuff he did. I want to be the safest, most effective aviator/NFO I can possibly be." That shows both humility and knowledge of Naval Aviation, which they like.
Also, beware of loaded questions. Such as: "So, what do you want fly in the Navy." That question is loaded because the board members usually don't give a damn about the answer. What they really want to know is how well this student knows the system and the Navy in general (most notably how the ever changing needs of the Navy dictate selection) and is willing to accept the misery, pain, and uncertainty of selection to come in API and Primary. If you quickly say: "I want to fly jets," it is never a smart idea, even if it is the truth for you. Everybody wants to fly jets. Everybody has seen Top Gun and wants jets so they can be sexy and score hot chicks. Blah blah blah. A good answer would be: "Sir/Ma'am, Jets are my top choice, but I'd be happy to fly anything with wings or rotors."
Never, never blame any instructors or anyone else for your stage check problems. You might be compelled to say: "So and so is a total prick and it is his/her fault I failed." Bad idea. I realized before going into it that you have to take responsibility even if it is to excess for every issue they could bring up. Writing down possible questions and formulating answers beforehand is a wise idea. Hell, if you could get some friends/fellow students and rehearse them, all the better.
I am not saying that you should try to say what they want to hear. Honesty is paramount. Strategize your conformity only if it is the difference between being arrogant and being humble.
If the board votes in favor of retention, you will then pay a visit to the ATS office and talk to one of the senior officers there. That was the scariest part for me, because even though the board had voted in favor of retention for me, the officer in ATS basically looked at my jacket, looked me in the face, and then looked at my jacket again and concluded that I am not aviator material and have little to no chance of succeeding and my personality type is not what they are looking for and people like me are incapable of change. Only after fifteen minutes of this abuse did he decide through clenched teeth to concur for retention. Whatever the ATS officer says, KEEP A POKER FACE. By that point I was so numb from the PRB that my face was pretty much incapable of showing emotion, so that made the poker face easier. Still, they look for signs of emotional weakness and try to probe them, so throw up the shield and keep it in place with everything you have.
If the ATS officer concurs, you will get your remedial time and your second chance. If ATS declines, you will pay a visit to the CO for the tie-breaker. I have no idea what this is like since ATS concurred for me, but I can only assume it would be similar to ATS in terms of how students should conduct themselves, with a greater emphasis on formality and professional courtesy.
Good Luck.