Coaching in my eyes is a trifecta of skills.
1. You're student of the game description- a person who understands the x's and o's
2. Motivator - this is your teacher. Can he communicate his ideas in a way that makes the player receptive and pliable. (there are techniques depending on level)
3. This is the most elusive one...talent evaluator. You have to have an eye for not only talent, but then understand (more student of the game stuff here), how those skill sets are needed, in what situations do they flourish, and how does the players total picture mesh with the needs of the team. I.e. You don't need a shortstop that hits .350 but is error prone if your lineup hits .350 without him...but you would need him if your lineup hits .250.