GMAT Mastery Workbook

Offers a 30 day long preparation plan with tips that will let you master GMAT all by yourself.
Offers a daily tracker, so you can stay focused and accountable.
Offers a sample error log/diary- a must have for self improvement.

This workbook offers tactical support to the already popular GMAT strategy book http://www.amazon.com/GMAT-Improve-Drastically-Business-School-ebook/dp/B00A7CTV1A