Hi Gmatz22,
Since your GMAT score has plateaued you probably have some lingering weaknesses that should be addressed in order to raise your score. I understand that you have completed a prep course as well as many questions in the
OG; however, you must remember that GMAT is such a challenging exam because there are relatively few questions asked in a given exam, yet those questions come from a huge topic pool. Thus, the best way to get a great GMAT score is to have a thorough understanding of all of the topics that may be tested on the exam. To develop such mastery, you want to strive for linear and targeted learning, and follow that with focused practice. In other words, you want to master one topic before you move to the next. Have you been able to study in this way?
For example, when studying verbal, focus on learning one section at a time: reading comprehension, sentence correction, or critical reasoning. When learning about critical reasoning, for example, you want to be able to learn about all aspects of critical reasoning (strengthen and weaken the conclusion, resolve the paradox, find the conclusion, must be true, etc.). Follow up your learning with focused critical reasoning practice, so you can determine your specific weaknesses within that topic. You should do the same for sentence correction and reading comprehension.
Follow a similar routine for quant. If you are learning about Number Properties, you should learn everything possible about that topic: LCM, GCF, units digit patterns, divisibility, remainders, etc. After that, be sure that you practice with at least 50 questions just on Number Properties. The results of that practice will help you to determine how well you have truly mastered that topic. Continue this process with every quant topic.
Also, you may consider using other study materials, besides
the Official Guide, as your study resource. While
the Official Guide is a great book because it has official questions from past GMATs, it has limited instruction and does not provide full exposure to all GMAT topics. For your retake, you may consider seeking out some robust prep materials that provide sufficient targeted practice for you to discover and fix your weak areas.
If you have any further questions, feel free to contact me directly.