Imo, just make sure that you cover EVERY concept that could possibly be tested. Don't neglect concepts that you don't like or don't think will be tested because of the lack of questions on the concept. You NEVER know what could happen on the real thing. There could be times when one concept is just tested crazy disproportionately compared to others, and depending on your luck, that concept could save or kill you on the exam. Don't let that chance happen just because you didn't really understand a concept due to lack of concentration on it.
As for the mentality, I was actually applying that idea to the entire exam. If you come in calm and collected and ready to be at least a little surprised, I think your anticipation of those little eccentricities will really help in allowing you to carry through the exam. How to get this mentality? You may have seen this idea throughout the forum a lot, but one thing I did that I definitely don't regret doing is just chilling on the day before the exam. Some people go out, watch games, chill with friends, do a hobby, etc. I just watched a lot of comedies and that really lightened my mood lolol. And then to the hours going up to the exam, I just listened to some motivational music and went in with cautious confidence, ready to take on whatever comes! We'll see how the scores come out, but this definitely helped me with whatever anxiety I would've had coming into the exam.
Like certain topics on physics/gen chem, orgo is really hit or miss in terms of how heavily it's tested and in what depth it's tested. You could get a test that has a couple passages and a few discretes in orgo or a test that has maybe just a couple of questions and a passage in it. Again, don't let the amount of orgo on the exam throw you off. Not sure what to tell you since I got comfortable in orgo from classes and lab work, but just go through the various mechanisms (i.e. SN2, SN1, addition, addition/elimination, etc.) and the lab techniques. Prepare for the worst, but don't go in with the idea that you're just gonna fail if there's a lot of orgo on the test!