In the same way that judges have different job functions from practitioners, deans have different job functions from faculty. All deal with the law, but in different capacities and with a very different skill base. Legal academics are trained to criticize decisions, not make them. When you become a dean, you must learn to make decisions. Only a few of those decisions are momentous.
Experience is a valuable instructor.
I vividly remember my first month as dean at Nova Southeastern University in the summer of 1986. I was greeted by a torrent of minutiae. I quickly learned that I would not be able to survive and function effectively as dean if I tried to micro-manage the enterprise. A key decision I made early on was to delegate the discretion to make decisions to a talented group of administrators. On the most critical issues, my colleagues learned that I needed to be involved from the beginning and ultimately to make the decision with their advice.