I haven't posted much here, but definitely used the forums as a resource from time to time, and especially when I first decided I would take the GMAT. As such, I thought I'd offer some tidbits from my experience. Since a lot of people have done exceptionally well and debriefed their preparation and exam thoroughly, my advice is targeted more toward people who have extremely busy schedules and little time to study. Working in investment banking and leading several church fellowships at the same time, I certainly found it difficult to find ample study time and even took a vacation day the day before my test.
First, a recap of my practice tests, with scores, dates, and the comments, often about the studying done in between:
GMAT Prep 1: 720 (47Q/41V: October 2010, no practice)
GMAT Prep 2: 720 (47Q/42V: May 2011, little studying)
MGMAT 1: 740 (47Q/45V: June 12, 2011, study focus on quant)
MGMAT 2: 740 (47Q/45V: June 19, 2011, still focused on quant)
MGMAT 3: 710 (43Q/44V: July 7, 2011, late night after work and gym)
MGMAT 4: 770 (50Q/45V: July 31, 2011, readjusted approach)
MGMAT 5: 730 (50Q/39V: August 7, 2011, minor studying but lethargic that day)
MGMAT 6: 750 (48Q/45V: August 10, 2011, exclusive verbal focus)
GMAT Prep 1: 760 (50Q/42V: August 12, 2011, just a final test)
GMAT: 760 (49Q/45V: August 13, 2011)
Being a highly quantitative person, I figured I would breeze through the quantitative sections and brush up a little on the verbal. Unfortunately, once I took my first two tests, I realized it was the other way around. I'd been out of math class for way too long, and data sufficiency problems posed a problem for me. On the flip side, scoring 720 both times provided me the assurance that, with a little brush up, I could raise my score a few notches.
As you can see from my results, my quant scores were a lot more stubborn than I expected. Although I wasn't studying too hard -- I simply didn't have the time -- I expected what studying I did to provide a boost. It wasn't until after the third MGMAT test (which I bombed) that I decided to do some analysis and found that I was getting a significant number of problems wrong late in the quant section. Basically, I was running out of time, without fully admitting this fact to myself. After a busy stretch in mid-July, I resumed studying in late July by registering for a trial account at Grockit and doing only timed math problems. Though I only spent an hour on the site, the time limit forced me to develop an internal clock when testing. Although I barely studied in July, I went back and took another test, and voila -- my quant jumped to 50. Quite confident that timing was my achilles heel all along, I registered for the test. And then ramped up my studying for the final two weeks.
Okay, so enough about my story. Here's my advice.
* Figure out what you need to work on. If you don't have much time to begin with, whatever time you're able to allocate to GMAT preparation becomes that much more precious. I bought the official guide as well as MGMAT Sentence Corrections and Number Properties, but quickly realized I didn't have the time to read the entire books and do all the problems. In fact, after realizing my verbal wasn't half bad, I completely ditched the SC book and studying for verbal altogether (aside from the period between August 7 and 10) -- a departure from my original plan but probably the right thing to do.
* Identify your weak spots and attack them relentlessly. Don't waste time on anything else. Your largest gains will come from shoring up any chinks in the armor, not polishing the nice areas. For me, I needed to refresh my memory on certain math concepts and learn effective test-taking techniques (which I think applies to almost anyone new to the GMAT). Although it may seem like my quant studying didn't help much (as witnessed by the four straight 47s), it was actually crucial to my ultimate success. There were certain types of problems that really needed work, such as combinatorics, and I made sure I figured out exactly how to do these problems. When I finally resolved my timing issues, it was in large part due to the fact that I could formulate an approach to almost any problem I encountered.
* Set aside set times to study. I really didn't do this until the final two weeks, and it really hindered my progress. If you're not consistently in the material, it's hard to build any sort of momentum. It's like playing golf. If you play once every three weeks, you'll feel like you're back at square one every time. (At least that's how I feel, ha.)
* Work on understanding the test format and managing your time. On a tight and/or short schedule, effective test-taking technique will boost your score a lot more than improving your conceptual knowledge.
* As a follow up to this previous point, take a lot of practice tests, but also be sure to analyze what you're doing wrong. As you can see, I scored 47 on quant four times in a row, despite only studying in this area. Ultimately, it wasn't because I didn't know the material, but because of poor timing.
* Test under real conditions. I think a lot of people note this, so yeah, just listen to them. Don't take extra long breaks, don't skip the AWA, and don't do anything else that you won't be able to do during the real test.
* Practice expending as little brainpower as possible to ably complete the AWA section. You'll need it for the rest of your test, so don't waste it there. Another reason why you should bite the bullet and do the AWA during practice tests.
* Eat blueberries. Okay, you don't have to. But you should.
Hope this helps in some manner. I basically highlighted some of my key takeaways, but I'd be more than glad to answer any additional questions you may have. Happy studying!