There are many methods that people use to pick their teams for their brackets. Some choose analytics, others who don't know much about the teams use the method of "Which mascot would win in a fight?" Basketball analysts, like Joe Lunardi, spend hours upon hours trying to come up with explanations for why teams would win. The real truth is, there is no method. March Madness is like Vegas, there is no method to winning. I like to hear the many methods that other people use. Usually I pick teams on the strength of their lineups and the variety of scoring options that they have. I usually make my initial picks, then I go back two or three times before the start of the madness to make sure I like my picks and make my final changes.
All in all, there will never be a person that picks the whole bracket correctly no matter the method. Sports are so unpredictable because one mistake can change the whole outcome of a game. There is no method to the madness.