I've coached softball, and managed a media relations office. Its all about getting people to believe in what you do- and that means believe in what you do as well.
As far as on the field, I've always thought that being strong up the middle is important- in football its he lines, QB's and safeties (and MLB)
in baseball catcher, pitcher, SS, 2b, and CF
basketball point guard and center
a good head coach can coach any sport, if they learn about the fundamentals. Its not hard, but you also need a lot of luck. My team went 8-0 by the way- my roster made me look like a genius, by the way....best assembly of talent in the league