Here's my story!
Took the test first back in fall of 2008, after taking a prep course. Scored a 610 (44 Q, 30 V).
Discouraged and burnt out, I threw my GMAT books into the closet, and it wasn't until a year and half later when I could finally muster the strength and willpower for a second go-around. This time, I took it to the house! 720 (49 q, 40 v)

Here's how my study strategy changed from the first to the second time.
First attempt
-studied about 3 months, from the beginning of my class to test day
-put in A LOT of hours, maybe 3-4 hours a day, more on weekends
-always timed myself on the problems (I figured since that's how test day conditions will be, might as well simulate it from the start)
-covered as many problems as I could - prep material, OG, practice tests, anything else I could find (I figured the more problems I saw, the better the chance of recognizing problems on test day)
-took the test on a Monday afternoon
Second attempt
-studied for about 6 months
-decreased the number of hours I'd study every day, about 2 hours on weekdays, a little more on weekends
-stopped timing myself (worked through every problem as best as I could, without attention to time)
-ramped down number of practice problems; repeated problems over and over again
-took the test on a Thursday morning
Decreasing the number of problems I did, and going more slowly through each problem definitely helped. Going over problems over and over again helped to really internalize the material.
As far as the actual test experience goes, it was weird. The test definitely plays with your mind..trying to figure out how you're doing and how difficult the problems are that you're going through. I think I ended up guessing on about 2/5 of the problems. And there were quite a few times when I switched my answer back and forth. I totally thought I was bombing the test.. so I was pretty ecstatic when I got my score.
My advice..
Do: spread out your studying, do less problems, spend more time on each problem
Dont: overload yourself with practice problems, don't try to analyze your performance during the test - just go through each problem and do your best!
The only negative is that I ended up getting a 4 on the AWA (after getting a 5.5 the first time around). I stuck to the standard intro, 3 paragraphs, conclusion format that got me my 5.5 the first time around. So not sure what happened there..