How would you feel if you fail the PMP Exam by just one question? Avoid this by using your exam time wisely. Here is one such strategy:
Four hours is plenty of time for you to read and re-read all questions. You should be able to go through all questions in your first pass in about two to three hours. During this first pass you will probably not know all answers to all questions. That's OK because that's what the "mark" feature is for. Use it to mark the questions you are unsure and then use the remaining time to review all those questions in detail that have stumped you at first.
Another strategy is to concentrate on the easier questions first (those that you feel you'll find the right answers for quickly) and then come back for the harder questions in your second pass. In this way, if you are confronted with a particularly puzzling question, you will simply mark it and move on to the next. Many test takers report that sometimes, a succeeding questions provides a clue or gives you the "nudge" that you need to figure out the difficult ones you have skipped.
Remember also, that some questions will appear to have two right answers. In this case you have to answer the question by trying to think like the PMBOK Guide. So if you have studied and understood the concepts from your PMBOK Guide, then there is really not much to fear before going into the exam room. And don't be surprised to come across questions that are framed in an unusual way or use terms that are unfamiliar to you. In these cases the examiners want to know that you understand the processes rather than just memorized them.
Last but not least: Remember to check, check and check again that you have answered all the questions. Make sure not a single one of them is unanswered. There is no penalty for answering a question incorrectly. So go ahead and guess on those questions where you really have no idea. Who knows... that might just be the question that lets you see "Pass" instead of "Fail" on the screen.