what material did you use to study? Did you keep an error log?

I used the official guide for gmat review, as well as the two smaller official guide books for quant and verbal. I also downloaded the practice tests from mba.com. The more i think back to the test, I feel like i didnt use any of the skills and I had studied for the last three months. Once i sat down, it was like i was taking the test for the first time. When timing myself and answering pracitce problems from the official guide books, I was doing well (80%-90% correct). Is there a particular book that covers strategy or overall logic of the test?

I did keep an error log. I would study is sets of 10 questions, reviewing the ones i got wrong at the end of the set.

Thanks for your response.

I would start off with Manhattan GMAT and cover one topic a week thoroughly. Then I would do practice problems from the official guide on the weekend. I would start off with 40 questions in quant and try to finish them in 75 minutes.