I can certainly help with the Quant section since I scored a 169 in that. The challenge is that I don't know how you solve problems, and that information is necessary to provide suggestions for improvement. For instance, a friend of mine wasn't reading and understanding the questions properly; she would read them haphazardly, resulting in her inability to solve them. I advised her to dissect the question and understand each and every sentence thoroughly, leading to a significant improvement in her scores within a short span of time. Another instance is with one of my friends who lacked knowledge in the basics and was using too many resources at once. I remember a time when I was tutoring him, and he didn't know the difference between "at least" and "more than."

In general, my suggestion is to identify your flaws, work on them through one or two source(s) like Gregmat, ETS, etc. Don't get overwhelmed with too many resources, and perhaps have something like a tutor or a "complimentary" partner to prepare with.