What Harvard Reject Wishes He'd Known

London-based Harvard/Sloan/Stanford/Wharton reject D.G finally found his “good fit”, Kellogg, after a painful three-year application process. So what does he wish he'd known about MBA admissions?

Do GMAT Prep tests over and over again, de-installing and re-installing the software to squeeze out as many new questions as possible. Also, The Manhattan GMAT Forums and The Manhattan GMAT Books are useful guides to the theory behind the questions.
Find someone inside the school you want to go to and get that person to put in a good word for you.
Details, details, details! Kellogg asks about your “career plan”, Harvard asks about your “career vision”, Stanford asks about your “career aspiration”, Wharton asks about your “career goal”. A good applicant will appreciate the subtle difference between these terms and answer accordingly.
Start hunting for financial assistance and scholarships ASAP! Deadlines for some opportunities are before even the application deadlines, such as those for the Rotary Club.