Before starting your MBA admissions journey, we highly recommend that you acquire some valuable resources:

THE Best MBA admissions book ever
Admitted! Diane and Chad’s Excellent MBA Adventure
Successful application essays
65 Successful Harvard Business School Application Essays, Second Edition: With Analysis by the Staff of The Harbus, the Harvard Business School Newspaper
Essential GMAT Preparation Guides
Manhattan GMAT Complete Strategy Guide Set, 5th Edition (Manhattan Gmat Strategy Guides: Instructional Guide)
The Official Guide for GMAT Review 2015 Bundle (3 books)
The Official Guide for GMAT Review 2015 Edition
The Official Guide for GMAT Verbal Review, 2015 Edition
The Official Guide for GMAT Quantitative Review, 2015 Edition
advice about how to select an admissions consultant
Finding the Best MBA Admissions Consultant
GMAT Club: Best MBA Admissions Consultants, 2019
GMAT Club: Best MBA Admissions Consultants, 2018