Lots of little things like
scouting efficiency,
how zone works, understanding how important stamina and fatigue are, etc. Honestly, probably the most valuable thing to me, in terms of hard wins and losses, was when I really started to look at the available efficiency metrics in the player game plan when setting the distribution; a number of ways to do it, but I like to take the PPG and divide it by the Off%, and use that to fine tune the distribution as the season goes along. And defensively, it shows me not only how my opponents are trying to score, but how they are effectively scoring.