Look at fit btw business schools and your academic/goals. You will need to decide btw 1 (Insead) or 2 year MBA. Teaching methods vary from pure case studies (Darden, HBS, IESE) to experimental group based learning (Ross, Kellogg), some are very analytical (Wharton, Booth). Generally, Kellogg is seen to have the best marketing group, reflected in profs, many marketing electives and recruiters. Also you need to think about GMAT, admissions tend to use it as a cut off, see median GMAT at each MBA. Good luck