Hey ib529,

I'll let some of the users talk about their experiences with OG12, but since you mentioned it I'd like to at least weigh in - while it's common for forum users to talk a lot about how much time they spent studying, it's exponentially more important (albeit harder to quantify in a forum post) that you spend high-quality time studying. Often times students prioritize quantity well over quality, and I think that hurts them more than they realize.

My suggestion with the OG (or any study book, really) is to first use the mock test and/or a handful (20 or so) problems of each type just to get familiar with what the test covers and how it's designed. From there on out, focus your study time on objectives, such as:

-Training yourself to think systematically about Sentence Correction
-Tracking the "silly" mistakes that you tend to make (or have to double-check) in Problem Solving questions
-Breaking down Data Sufficiency questions to "click" with the logic
-(later in your study) Completing sets of math questions in <2 minutes each

Try to close each study session by noting things like:

-What 2-3 concepts did you learn and feel are most important moving forward?
-How can you better approach that type of question in the future?
-Which areas will you need to emphasize in your upcoming study sessions?
-Which strategies can you carry over to other questions in that family?

Try to focus on objectives and not just "time spent" or "problems completed". You'll probably see quite a few posts on here lamenting "I've studied for X number of months, taken Y number of practice tests and used all of these books but my score hasn't budged" - notice that those students typically just list the volume of what they've completed but have little in the way of self-analysis of what they've learned or specifically what they need to improve upon. Hold yourself accountable for learning and not just doing, and you can avoid that problem.