'I scored 780 on the GMAT, with 3 months' prep'

I kept taking the Kaplan tests every weekend and made sure that I practiced consistently and give ample time to analysis of the tests. Kaplan tests are not a true representation of the real GMAT. I scored 620+ in each of the tests which could be safely mapped to 720 in the real test.
I had joined an online group of "would-be-GMAT-takers" which proved to be a good way to practice sentence correction during 5-minutes breaks that I took every two hours from my office work. There were similar forums on scoretop.com as well. I could run through two questions in each break. This might sound like "only-two-questions" but this way, I could go through a lot of questions in a span of three months even with a hectic work schedule. I believe that joining this group and actively participating in the forum was one thing that helped me the most.
Two weeks before my exam, I rushed through the quant and the AWA part. Quant and AWA was more or less covered in the Kaplan tests that I took, so the preparation took me not more than four days. I relied mainly on Official Guide for quant. Ten days before the exam; I once again went through the verbal part of Official Guide thoroughly. I felt that I was almost done with the material I had, so I got a few tests from 800score.com from a friend. I didn't have the analysis of the answers so took them merely as practice tests. Two days before the final exam, I took the second test of Powerprep where I scored 750. 

I had been keeping a record of all the mistakes that I had done during the tests and the things that I learnt while analysing my mistakes. Every weekend, I used to revisit this document to check if was making the same mistake. For the last two days, I carefully went through this document to see if I had done justice to my preparation. Eventually I scored 780.