hey there. i just took the gmat last week and got a 640. Unfortunately, I am aiming for a 680-700. To improve, I am going to focus on my week areas for a few weeks, then in the last week go back to my strong areas to review.
What I would recommend to you is is what I'm doing. Focus on your weak areas, then go back to your strong areas and review. Review your concepts and do as many practice [problems as you can. Try to do them in sets of 37 -41 to simulate testing endurance.
I would practice with OG and use Kaplan Quant. The kaplan verbal is pretty damn off from the real thing. I know cause I took the kaplan classroom course and have the 2005 book as well. and of course..use gmatprep test in the last week.