There are lots of ways to prepare for this test, both on and offline. I have attached some online resources, and you can find many more by searching "free GRE test prep" with your search engine. You should also visit your local library and/or bookstore for reference materials and books printed by companies like the Center for Applied Research, Kaplan, and others which will help you get a handle on your weak areas as well as help you strengthen your strong points.
Give yourself plenty of time to review vocabulary and math skills--I always encourage my students to create portable flashcards. The night before the test, get lots of rest. Eat a good breakfast and be on time for the test. They will not admit any latecomers.
As a tutor with examville.com I get such queries everyday.I would like you to touch upon the following points while preparing for GRE.
1) Take as many practice test as you can, that increases your logical and reasoning abilities.
2)Try to time your questions so that you can complete the questions on time.
3)Join any GRE group to be in the touch with the recent updates.
If you have any other questions regarding the same you can enroll for the online classes at examville.com.
I recommend www.examville.com if you are preparing for a test. They have online standardized practice exams, review materials you can download and upload.
If you have had Latin, you may be more suited to take the MAT.