One strategy that helped me greatly on the PMP exam as well as other certification tests is to perform a "Brain Dump".
As we all know, you cannot take reference material into the exam room; but, if you are like me, I am better able to answer situational questions if I have something that sparks my memory. We obviously cannot predict what questions we will get on the test, but in my case, it isn't necessary. With a good understanding of the material, a small piece of related material is all I need to start the synapses firing.
To facilitate this, I recreate the basic charts and formulas in the test room from memory. This involves taking a few of the more helpful charts and formulas that you would use as reference and memorize them; then, just before you begin your test, use the supplied pencil and scratch paper to write them out. As you take the exam, you will have a small set of reference material to use.
For the PMP, I memorized the process chart that lists the process groups and knowledge areas and all of the main processes. When I get a question that references any of the processes, I look at the self made chart which immediately sparks the brain into working.
I also memorize the most common formulas for Earned Value (EV). Memorizing the charts and formulas is made easier if you break each line or cell in the table to a memory mnemonic; for example, the process groups can be remembered with the phrase "If Syria Took Croatian Quartz, How Could Russia Protest". In each word, the first letter is from the name of the process group in order; "I" is for "Integration" and so on.
With the typical anticipatory anxiety that comes with any performance event, having a set of reference material to look at is a great coping mechanism and confidence restorer.