I completed my GMAT 2 hours ago. I scored a 750 (50 Q, 41 V) 98th percentile overall. I achieved this score with less than one month in preparation.
The following was my study plan:
1) Complete OG questions - all of them including the Verbal and Quant only books
2) Manhattan Sentence correction
I took 4 practice tests in all -
710 - First GMAC test - prior to preparation
720 - Second GMAC test - 1 week into preparation
640 - First MGMAT test - 2 week into preparation
760 - Repeat GMAC test - 3 week into preparation
My takeaways are:
1) Don't spend time on solving the most difficult questions - spend time in avoiding silly mistakes
2) Don't take MGMAT tests - the real test is nowhere near that level and it only demoralizes you
3) Play to your strengths, not your weaknesses - for example - I am not particularly strong in sentence corrections - so I made sure, I didn't make any mistakes in RC and CR.