The 60-Day GMAT Study Guide

Hello, once again I decided that I will beat the GMAT.
But this time will be victorious. No more procrastination!

The main question that I have is about the work on my mistakes.
What should be the best approach for the review of the mistakes and guesses.

Day 1&2. I did a diagnostic test:
Quant. Q: 13/24 (13 right out of 24); DS: 7/24
Verbal: RC: 12/17; CR: 12/17; SC: 9/18.

Question: Should I review all the questions? Because I saw that I will do this test again later.

On Day 3 I posponed GMATPrep exam because I didn't have the time and will to take the test head on.

I did Day 4&5, and again I faced the same question. How should I review my answers? What is the best approach?

At this point I forced myself to take GMATPrep exam and got the Baseline score of 570 (Q:38, V:31).
On Quantative section I got 17 questions right out of 37 and on verbal - 26 out of 41.

p.s. Somehow, this post is like a journal. Sorry for that.