Coaches check their egos at the door. They resist trying to impress a student with their knowledge. When coaching is done well, learners believe they personally have discovered ideas and answers, hence, they may never acknowledge the coach's contribution. And that should be just fine with the coach. Coaches ask questions.
Coaches listen completely.
They resist the temptation to give instant advice or answers, even if they have them at the tip of their tongue. They give the student time to get a point out fully, and only then work to develop a coaching conversation. They resist phone calls, door knocks, and the errant material lying atop their desks. When coaching is underway, the most important gift a coach gives is complete attention. Coaches are positive.