I can make a few suggestions as how to go about the GRE preparation. First and the foremost principle of cracking the GRE is practice you can take tests online, plenty of sites have them. However examville has timed questions and the answers are with explanations, facility of live classes with subject specific experts. All the best.

This is basic tips for any important test is to get plenty of sleep the night before, eat a good breakfast and relax. I will give you some links to free information about the test and tips. ( I had to weed out the ones that wanted payment).

I would also advise taking a credited pretest. This helps you know what to expect on the test ahead of time. I think it would be a perfect way to prepare. You can download free practice booklets at this site which is legit : http://www.ets.org/gre/subject/about/downloads/index.html
http://www.ets.org/gre/general/prepare/sample_questions/index.html

http://www.ets.org/Media/Tests/GRE/pdf/gre%20practice%20general%20test.pdf

Beware of places online wanting money, such a rip off!

http://graduate-schools.suite101.com/article.cfm/how_to_improve_your_gre_math_scores

http://graduate-schools.suite101.com/article.cfm/gre_prep_for_reading_comprehension

http://graduate-schools.suite101.com/article.cfm/how_to_improve_your_gre_verbal_score

http://graduate-schools.suite101.com/article.cfm/the_gre_and_the_issue_essay

hey Joey! Don't be nervous , Few tips i want share with you :
Preparation Tips

Prepare extensive to ensure that you get the highest score possible. This is not the time to cram.

Buy a GRE review book.
Download sample tests. ( you can download it from www.examville.com)
Try a practice test under conditions similar to the actual GRE. Based on your practice score, devise a study plan to help you brush up on vocabulary, reading comprehension, analogies, algebra, and geometry.
Plan to take the GRE well in advance of application due dates. Try to take it the spring or summer before you apply to grad school. You can always retake the GRE, but remember that you're allowed to take it only once per calendar month. Because all prior scores are sent to the institutions to which you're applying, never take the GRE as practice.
Here's How:

Understand the Test
Step 1 is to understand what you're getting into. Get acquainted with the GRE and begin preparing with this thorough overview of the Graduate Record Exam. Most students are overwhelmed with questions about the exam. Seek answers to . The newest GRE section, the Analytical Writing section, is the source of much confusion among applications. Knowledge is power. This article on Analytical Writing section will help you get the info you need to excel.
Practice
Get a handle on the test by practicing with sample test questions and exams. Learn about your weaknesses and devise strategies to overcome them.
Consider a review course
GRE review courses can aid your preparation and help you overcome gaps in your competence.
Strategize
Learn strategies for tackling the GRE. The Vebal Section is particularly challenging, so spend time learning strategies for the Verbal Section.
Make Time to Relax
An essential part of test prep is to take care of your own physical and mental health. Learn how to reduce stress and relax.
Tips:

Begin preparing several months ahead of time to give yourself the opportunity to prepare well.
Take the GRE well before graduate admissions applications are due to ensure that you have time to take it a second time if needed.
Compile your materials for the exam (paperwork, photo id, directions) the night before to minimize rushing around the morning of the exam.
Arrive to the test site early to reduce anxiety and get settled.
What You Need:

Access to Practice Materials
Time
Patience
Motivation and Endurance