I suggest a systematic (even methodical) approach, in which you take the time to master each topic/concept (e.g., percents, ratios, assumption questions in critical reasoning, comparison questions in sentence correction, etc).
So, for each topic/concept, you should:
1) Learn the underlying concepts (rules, attributes, notation, etc.)
2) Learn GMAT-specific strategies related to that topic
3) Practice dozens of questions all related to that one topic.
4) Don't stop working on that topic until you have mastered it
Then, and only then, move on to the next topic.
To help you focus on one topic at a time, you can use BTG's tagging feature. For example, here are all of the questions tagged as statistics questions:
https://www.beatthegmat.com/forums/tags/ ... statistics
See the left side of that linked page for more tag options.
You should also use an Error Log (aka Improvement Chart) while completing questions from the Official Guide (OG). You can find a free downloadable Improvement Chart here:
https://www.beatthegmat.com/mba/gmat-error-log. This will help you identify and strengthen your weak areas.
I also suggest that you spend a lot of time reviewing the responses from the Experts on this site, since they often model the steps you should be taking when answering questions.
Finally, in addition to learning the core concepts and GMAT-specific strategies, be sure to work on your endurance and test-taking skills (e.g., time management) by taking several practice tests. If you're interested, we have a free GMAT time management video at
https://www.gmatprepnow.com/module/gener ... es?id=1244
Cheers,
Brent
