A good coach must be proficient technically. They must know the rules and know how to create a game plan that legally exploits those rules based on the opponent. Those are the basics that almost every good coach understands.
What separates a good coach and a great coach is the coach’s ability to teach and intrinsically motivate. It’s that simple. If a good coach develops the uncanny ability to transfer what’s in their head into another persons head, they are on the path to greatness. What’s more, if a good coach also develops the ability to intrinsically motivate others to exceed expectations, they move into the top 1% of coaches.
A coach with this combination is rare. Technically proficient coaches who know how to game plan are a dime a dozen. What’s truly unique among great coaches is teaching and motivating.