Start your GRE preparation process by taking a practice test, which will gauge your knowledge level and let you know what areas will need improvement throughout your studies. You should continue to take different practice tests on a weekly or monthly basis--depending on the length of your study plan--to gauge your progress.
Once you know your strengths and weaknesses, make a plan of action for your GRE studying. Decide how much outside help you need---if any---and plan accordingly. There are a variety of test prep resources such as private tutoring, GRE classes, study groups, online tutorials and test prep books. You should choose the method which best fits your learning style to maximize the results. Do not procrastinate on starting your study plan, it is crucial to start early.
According to the Princeton Review, the revision of GRE vocabulary is one of the best methods for increasing your GRE verbal score. Create flash cards and lists to learn new words, and write sentences to put the words in context once you are more familiar with them.
The written component of the GRE is an opportunity to express yourself beyond the constraints of a standardized test. Practice drafting outlines and writing essays on a variety of topics so you are familiar with the process and the time limits.
Practice your reading comprehension skills by reading materials and actively considering the important information, such as the theme or the purpose of the article. Choose GRE-level material such as The Economist or The Wall Street Journal.