The best way to study
You should spend at least 50 to 60 hours preparing for the GMAT, but for added confidence you may want to enroll in a test preparation program. GMAT test preparation services can be expensive, but are worthwhile they make the difference between an adequate score and a great score.
Studying is certainly a requirement for success, but there are some tips that can help you maximize your performance on the test:
Process of Elimination
The GMAT doesn't allow you to skip questions, so you will have to provide an answer for each one. When you come to something you don't immediately understand or have an answer for, try to eliminate answers you are sure are incorrect. From there, if you can't possibly figure out the answer, just make your best guess and continue on with the next question.
Budget Your Time for Tough Questions
Know that, in each section, you'll have a percentage of questions that will give you trouble. Be prepared for these, recognize them when you come to them and learn from them as you move throughout the test.
Keep in mind that part of the GMAT is a test of your ability to know when to cut your losses. If you don't know the answer to a question, move on before too much time passes. Try your best as quickly as possible, then focus on getting to the questions you do know.
Use Scrap Paper
Keep track of your thoughts and impressions, and write down what you know for sure with respect to each question. Also, use rough notes when you undergo practice tests for the GMAT so you can learn your own ways for using the scrap paper effectively during the test.
Experimental Questions on the GMAT
One third of each set of GMAT questions are experimental. The Graduate Management Admissions Council uses these questions to test-drive future versions of the test. You won't be told which questions are experimental and which ones are official, so you should treat each question on the test as legitimate. However, answers to experimental questions will not be factored into your final score.