The One Thing You Wish You Knew - GMAT Club Contest!

After having scored 620(Q49 V24) and evaluating my mistakes, I realised that the biggest mistake( I actually Wish I knew this mistake before) was solving more and more questions rather than doing less and reviewing more.
I feel this is the most common mistake that most of the test takers make. YES, THE MOST COMMON MISTAKE!!! ( Surprisingly, we all know it but still we act so different, gotta give away quantity over quality)

I must have done atleast 10, 000 problems in total but look at my dismal performance. This approach is linked with the approach we used during the school days, an approach not applicable to gmat. The gmat is actually a test of how we think and by doing hundreds of thousands of problems , we learn NIL, i repeat NIL. we learn only when we start analyzing the problem, thinking and reviewing the problem, trying to find the alternate solutions, trying to rectify our mistakes and taking lessons away and so on...