Obtain and organize your study materials and time so you have time every day to study a set number of words. If you choose to read the New York Times or Wall Street Journal on a daily basis, write down unfamiliar words and their definitions. It's easier to remember words and definitions you've written down.
Break down your required words into sets of 50 words which you will study every day. Get a friend or relative to help you learn your words
Learn your words in context. As you study, find ways to use your words in sentences so your brain remembers them more easily. It's easier to remember words in context rather than trying to associate them with their definitions.
If you are short on time before your exam, study from flash cards or the GRE vocabulary list. If you decide to use Barron's vocabulary list from the "How to Prepare for the GRE" book, remember you only have to know general definitions, not exact ones.
Work for at least one hour a day on your word list. If you use Barron's book, work on one list a week. Each list contains 50 words. As you progress through the lists, review previous lists so that you retain the words more readily.