Hi mimishyu,
To start, the
OG books are great sources for practice questions, but they're not designed to teach you Tactics, patterns or the little 'secrets' behind the GMAT - for those, you'll need Course-oriented materials. In addition, the Diagnostic Test at the beginning of the main
Official Guide is NOT a proper representation of what you will face on Test Day - it's on paper, does not adapt, includes far more questions and does not present concepts in the same 'ratio' that they will appear on Test Day. This is meant to say that you should not use that paper Exam to assess your current 'ability level' - to gain that data, you should take a realistic, full-length practice CAT/mock under test-like conditions.
Before I can offer you any additional advice for your studies, it would help if you could provide a bit more information on how you've been studying and your goals:
Studies:
1) How long have you studied? How many hours do you typically study each week?
2) Have you used any other study materials besides
the Official Guide?
3) On what dates did you take EACH of your CATs/mocks and how did you score on EACH (including the Quant and Verbal Scaled Scores for EACH)?
Goals:
4) What is your overall goal score?
5) When are you planning to take the GMAT?
6) When are you planning to apply to Business School?
7) What Schools are you planning to apply to?
GMAT assassins aren't born, they're made,
Rich