I just returned from my GRE exam, and I was very happy to see that I had scored so well.
I graduated in the beginning of June, so I budgeted 2.5 months for intensive GRE preparation. I think the main factor behind a high GRE score is practice. I would zealously go through the practice sections of the textbooks, swallowing up the exercises and going back to review which were my weak points.
I studied almost all waking hours for the last 3 weeks, due to the short amount of time I had budgeted for GRE prep. I didn't spend any time poring over word lists, but just practiced several hundreds of verbal questions and immediately looked up any words I encountered which I didn't know. I also used Magoosh's free apps available for android, which I installed on my tablet.
For the Quant section, again, I found the best strategy to be practice. I would do all the exercies I could get my hands on and then review which parts I had problems with, then go back and do a few more exercises from those parts.
I scored 331 in each of the two Official Guide Practice Tests, and 335 on one Powerprep 2 practice exam, which perfectly matched with my real GRE score of 335.