GMAT score 620. Need help with new strategy to score 700.

I think 2 months is enough time to increase your score to the 700 level.

Now that you've identified your weaknesses, you can use BTG's tagging feature to focus on those question types. 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.

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 question.

When it comes to Reading Comprehension (RC), I don't believe that there's one specific approach that works best for everyone. I always recommend that students spend some time experimenting with different strategies to see which one best suits their memory, reading speed and English proficiency.

If you're interested, we have a free set of videos that cover all sorts of Reading Comprehension strategies: https://www.gmatprepnow.com/module/gmat- ... prehension

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