Thought I'd share my experience on my two attempts and what worked for me in improving my score.
1st attempt was March 30 2014. Used the official GMAT guide only. Studied for 2 months, about an hour a day on week days after work and 4-5 / day on weekends. I did ok with all the verbal questions so I mainly focused on quant. Scored 710 on first GMAC free test, and 740 on second test. Didn't prepare for IR apart from the two mock tests, and for AWA I read a few sample essays the weekend before the exam.
Went in on exam day feeling pretty ok, but:
1. Ran into a few questions which were not covered by
the official guide (lesson learned:
official guide is not enough)
2. The whiteboard really messed me up and I couldn't make head or tail of lots of my workings. Disaster.
3. As a result, ran out of time towards the end of quant and left 2 questions unanswered.
4. Thoroughly demoralized and half heartedly went through verbal.
Score: IR 6, Q 46 (68th percentile) , V 42 (96th percentile), overall 710
Decided to retake mainly due to the lousy quant score. I went though the entire
Manhattan GMAT guide, then Jeff Sackman's total gmat math. Then, I purchased his whole set of challenge questions (10 sets x 100 questions) and went through all of those.
After 1.5 months of drilling I was getting pretty burnt out, and decided any further improvement was going to be incremental. Took the
Manhattan GMAT mock test over the weekend, did horrible. Questions were way too complex and not sure how anyone would be able to solve them all in the time allotted (I had to guess something like 8 questions in a row to finish on time). Nevertheless, I went ahead with my 2nd attempt today, and scored:
IR 6 (same lousy score), Q 48 (76th percentile), V 47 (99th percentile), overall 760 (99th percentile).
Needless to say, I am pumped! I think what helped the most was:
1. Jeff's material - it is great, the questions are exactly the right level of complexity and they train you to be very careful and avoid falling into traps.
2. I kept an
error log, and I did all my questions in sets of 20 - 30 and timed myself.
3. Trained myself to know when to take a conscious decision to guess and move on (for me this is usually if I fill more than half a page with calculations. For today I probably took an educated guess on 2 of the quant questions once I realized they had me stumped).
4. I bought the
MGmat whiteboard (well technically it's yellow) and practiced on that.
I never struggled much with verbal but the main tip I would give to people is that you can eliminate a lot of the answer choice by looking at mismatched singular / plural phrases. E.g. "the black bear lives in a mountain as they thrive on the berries found there" is incorrect because "the black bear" and "they" should not be together. Also, you can eliminate answer choices based on figuring out whether a verb modifies the correct noun.
Hope this helps, and good luck!