Don't freak out.
I have it written on an index card sitting above my desk, and I might have to write it on the first page of my test so that when I get to a question that I do not know, I don't freak out.
One of the biggest mental hurdles of the bar exam is coming to terms with the fact that no matter how hard you study, you cannot just know it all. You can make and review a billion flashcards, outline every subject, make charts and graphs, do all the assignments Barbri gives, but it is impossible to know it all. There is just too much. Just as important as learning the materials is knowing what to do if you get to the test and do not know it.
As one lecturer pointed out, this concept is the most difficult for law students who did well to grasp. I think he rightly pointed out that people who tended to do well in law school were used to going into a test feeling like they knew everything based on preparing for that one test. Since most professors liked to test on material they covered in class, things appeared manageable and there never seemed like there were any surprises. So many of us are not used to getting a test with a question and having no idea how to start. Out of the dozens of tests that I took in law school, I can only think of one that I ever thought was "unfair" (and my Professor was really crazy).
But alas, law school exams and the bar exam are two completely different things. I am really trying to take the advice of the lecturers who advised us to keep practicing, and working through that feeling of the unknown. What to do when I get to an essay where I have no idea what they are talking about (make up rules, apply all facts, argue both sides, get stuff on paper with headings) or a multiple choice problem that is challenging (try to remember the rule, use process of elimination, and just move on and don't harp on that one question).
And like they said, chances are that if I do not know it, neither do most of the people around me. "Don't turn into a puddle on the ground. Sit up in your chair and answer the question!" -Prof Honisgberg.
Perhaps in all the craziness of the bar exam, there is a life lesson for those law students like me who like to prepare and have control of every situation. That can only get you so far.
[sorry for the bad quality of the picture. I use my phone's camera when I am too tired to get out my real camera]