Buy test-preparation materials. When selecting a GRE preparation guide, look for a guide that will give you tips on strengthening any weak spots. Peterson's Guides and guides from The Princeton Review, a test-preparation company, are both widely available in bookstores on and off college campuses. You can also visit the website of the creators of the GRE, Educational Testing Services for tips and preparation materials.
Take the practice tests in the GRE guides. Find out where you stand and what areas you need to work on by taking the included practice exams. After scoring the tests with the provided answers, you will know which areas can be excluded from your studies and which areas need more attention.
Follow the suggestions in the guides. For your weak areas, look through the guide and follow the offered suggestions for improving your scores.
Continue studying until you improve enough on the practice tests to earn the GRE scores that you need.