Hi all,
I have never before posted, but these forums have helped me immensely. My story will be brief because I have to go out to celebrate now, but here goes:
I started studying around July 2014, going through the OG and using
Magoosh. My studying was not very structured at all, and I was focusing on questions I knew rather than my weaknesses simply because it made me feel better about myself !

My diagnostic test score was 560 with 30q and 37v (if I recall correctly). I kept studying and managed to reach 680 (q44, v39) on GMATPrep, though there had been repeat questions so it was probably inflated.
Come test day, I felt prepared but still in the back of my mind felt that I will probably have to do it again to get 700+. Firstly, this test center opened very recently (Cape Town, South Africa). I wasn't given ear plugs, and the place was noisy. The door was broken so it kept popping open, and during the quant part I desperately needed the toilet. Everything worked against me that day which led to me getting 600 (q30, v41). However, even so, my practice tests had never been higher than 680, quant never higher than 44, and verbal never higher than 39, so at least I was happy about verbal.
Today, approximately two months later, I scored 730 (q48,v42). Let it be noted that I never studied verbal, so I can't comment on that, but my quant was and still is weak. To mitigate the poor test taking conditions of last time, I tried to have a good nights sleep, a nice all bran and banana breakfast, bring powerade and energy bars, as well as wax ear plugs. Every single detail of the day was planned to make sure I didn't get into the same kind of trouble as last time.
During the test I didn't feel like I was doing that well, some really easy quant questions made me worried but at the end of both sections the questions seemed pretty tricky so that gave me some courage. Never thought I'd score 730 though, I was hoping maybe 680 if lucky. My highest score ever on GMAT practice tests were 720 overall, 47 quant and 39 verbal, but never in the same test. So on test day, I scored my maximum ever. Two days before the exam I did two GMATClub quant tests, and score 29, and 15 respectively !!! I was so depressed, but I figured it was just exhaustion. Therefore I did no studying on the day before, and two days before I went out drinking with a friend. Letting my mind rest and my nerves cool was the smartest decision I made, in my opinion.
As much as I wish I could give some real advice, I really think I got lucky. I do however think it's important to not underestimate the importance of a good breakfast, cool nerves, and mitigating silly things that may take away from your focus. Another thing I would suggest is to give all your attention to the question at hand, and nothing else. My timing was perfect because of this fact alone.
Materials used (Only quant, no verbal):
MGMAT GuidesMagooshGMATClub testsMGMAT iPhone app
GMAT Math Bible
And best by far - GMATClub Math Book by Bunuel, Walker, Shrouded1, BB
I am just so happy I don't have to study anymore, was having math nightmares !