Review the structure of the test. The verbal section consists of 41 multiple choice questions that measure three distinct skills: reading comprehension, sentence correction and critical reasoning. If you are familiar with the format of each question, you will have a better chance at answering it correctly. Since you are allowed only 75 minutes for the verbal section of the GMAT, you don't want to waste time trying to figure out what the question is asking you.
Study your grammar. While most test-takers can easily form an eloquent sentence, identifying each part can be a little bit more difficult. In grade school, we spend hours pouring over these texts, only to discard them once we can craft an essay. But knowing the difference between a preposition and a participle can be essential on the GMAT. Pick up a copy of The Elements of Style by William Strunk Jr. and E.B. White. You don't need to memorize every page of this short book, but a quick refresher on the parts of speech will go a long way.
Take advantage of free resources. The GMAT's official website, MBA.com, offers free preparation software for test-takers looking to study. All you have to do is set up an account, which will then enable you to make, reschedule or cancel test-taking appointments as well. Your local library is also likely to have GMAT preparation books, so take a trip down there and see what they have to offer.
Enroll in a prep class. Educational companies like Kaplan, The Princeton Review and Manhattan GMAT all offer specialized GMAT preparation classes. If you can afford it, these courses are designed to specifically prepare you for each section of the test. They are by no means necessary to do well on the test, but they definitely can't hurt.
Practice, practice, practice. Purchase a few books of practice tests. Create a testing schedule for yourself and stick to it. The more often to take practice tests, the less likely you are to be surprised on the day of the test. Taking practice exams will not only help you learn the material, they'll also teach to what to expect from the format of the test. Since the verbal section largely consists of proven knowledge, they are unlikely to change from year to year. This means that practice tests will be very useful in preparing you for the verbal test.