If you're not getting a perfect Verbal score, then an extra 10 to 15 minutes will help improve your score. In a perfect scenario, you'll enter your last answer with under a minute to spare. To help keep you on track (and maximize the time you have to answer questions), I suggest that you use a Milestone Chart. This is covered in our free GMAT time management video at https://www.gmatprepnow.com/module/gener ... es?id=1244

Quant-wise, I believe that you should compartmentalize your learning and take the time to master each topic (e.g., percents, ratios, exponents, statistics, etc.). This means that, for each topic, 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.

I also suggest that you spend a lot of time reviewing the responses from the Experts on this site. They model the steps you should be taking when tackling math problems.

Cheers,
Brent