I am returning to grad school next year after a long hiatus from any kind of formal education (I received my undergraduate degree in 1991) so although I generally have been pretty successful with standardized tests, I was a little nervous about the GRE, in particular about the quantitative analysis portion. I haven't had a math class in over 25 years, since I majored in literature and communications as an undergrad, and was in an honors curriculum which allowed me write papers about math instead of taking a "real" math class.
I took the revised GRE a few weeks ago, so I haven't received my official scores yet, but the range estimates I was given after completing the test were numbers I was happy with (750-800 verbal, 710-800 quantitative). I won't have the official scores until November. These numbers were fairly close to the practice score numbers I got taking the official ETS sample test, and a bit higher than the practice scores I got taking the Kaplan practice tests.
EDITED TO ADD that my final scores on the new scale were 168/170 verbal, 157/170 quantitative, and 5.5/6 on the analytical writing. As I said above, I am not, nor have I ever been, very good at math, so although the quantitative score is only what I'd consider on the high end of average (77th percentile), for me, this score was far beyond my original expectations, so the studying I did paid off enormously.
Here is how I studied:
1. I downloaded and took the free ETS test as a baseline. I also downloaded and studied their free math review materials.
2. Based on step one, I reviewed my options here on Amazon for supplemental study materials, and decided I wanted about two months to study. Any more than that, and I think you run the risk of overcompensating and second-guessing yourself too much.
3. I chose this book as well as CliffsNotes Math Review for Standardized Tests (Cliffs Test Prep Math Review Standardized). I did not feel I needed extra prep materials for the verbal portion.
4. I worked through this book, including the practice test in the book, and all the in-book excercises.
5. I worked through the Cliff's Notes book; due to my ineptitude at math I worked through the entire book but if you are good at math, that would of course be unnecessary.
6. I worked through these much more quickly than I expected, so I also purchased, after about three weeks of study, Barron's New GRE Flash Cards, 2nd Edition and Gruber's Complete GRE Guide 2012. They were both useful although I did spend more time with the Kaplan book and the Cliff's Notes book.
7. I took a practice exam every couple of weeks. This was more to get used to sitting a 4-hour exam than anything else, and that was helpful as an exercise in endurance.
8. I worked through the CD of included practice exercises with the Kaplan book. These were very helpful, although I must caution you to take answers and results with a grain of salt. I felt that they often contained typos, and also that the verbal questions were often ill-conceived or explained strangely. So think of them as "practice" and don't get too worked up if you get answers wrong when you felt they should be right. Based on my verbal score estimate, I feel I am justified in making this statement.
9. The day before the test, I took one final practice test from the online tests available when you purchase this book.
In total, I spent 3-4 hours a day studying for this, for two months, and I work a full-time job so I was more than ready to be done with this exam prep. I do feel it was worthwhile, however. I would estimate that my scores improved from the original time I took a practice test, to the estimated real scores, about 50 points on the verbal section, and at least 200 points on the quantitative section (but as I mentioned, my original quantitative result was pretty dismal, whereas my verbal was quite good in the first place, so I focused my study on quantitative). Remember, the "numbers" will be totally different for my actual scores once I get them since they're changing the score scale, but this should give you a good idea of the improvements I feel that studying helped me make.
I do feel it was helpful to write several practice analytical writing essays, just to get a feel for how much I could realistically expect to write in 30 minutes; however, I don't know my scores there yet since they are hand scored so I don't have an estimate.
If I had it to do over again, I would probably not bother with the Gruber book, but the other three purchases I made were helpful. In short, I strongly recommend taking at least 4 or 5 hours to study by downloading and using the free ETS study materials, then deciding from there a) how much improvement you want to make, and in which particular areas, and b) how much time you are willing to devote to study. I think I'd have easily scored well enough to get into my desired programs with no study at all, but I wanted to see if the test prep would truly help as advertised, and I also wanted to see if I still liked studying as much as I did 20 years ago before I bothered applying and paying tuition for grad school!