What worked for me...
(1) Improving 'untimed accuracy': That requires ignoring time constraints during practice tests and just focusing on getting questions right, until the accuracy in both quant and verbal reaches 90%+. Stressing over speed when your accuracy under untimed conditions itself is low is not useful in my view. Speed will come with familiarity.
(2) Finishing the Test: GMAT algorithm penalizes meaningfully if you do not finish the test. I finished both sections with some time to spare. That required making some educated guesses. And that's alright. Not finishing GMAT is almost a crime for any 700 scorer. It makes a difference of 20-30 pts in my opinion.
(3) Focused prep: To get my untimed accuracy up towards 90%, I had to work on my weak areas. I spent nearly 80% of my time working on question types that were bogging my accuracy down. Don't spread out too much - Identify weak areas and focus your prep.
(4) Stamina: Without stamina, we can lose focus by the time those tricky CR/SC questions come around. Stamina=Focus, so do not underestimate it's importance. And btw, Energy drinks do work!
(5) Using the right materials:
SC - Nothing beats Ron Purewal on Manhattan Forums. Not even Manhattan's own guide. Go through his explanations to atleast 50 questions and you may not require much else.
CR/RC - LSAT questions and Old GMAT paper tests are very useful. Powerscore CR Bible is also fairly useful in organizing your thinking in dealing with various question types.
Quant -
GMAT Club tests are almost worth their weight in gold
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GMAT score is one variable in our direct control. We should work to maximize it.
Thank you, GMAT Club