The best way to learn anything is to teach it.
There are two ways to go about that that I can think of. One is to tutor people. The second is to write a book and/or design a course.
That’s right . . . you’re on to me!
I’ll say more about tutoring elsewhere (under the tag 'coaching'). But for now I’ll suggest that you do it on a level platform. That is to say, don’t imagine that you are some sort of teacher. You don’t know it all. And you don’t know others as well as they know themselves. So be a little humble and make your sessions a partnership. Be a team player.
As for writing a book, the challenge is to give advice that is universal for all individuals. I believe that this is possible, but “these things must be done delicately . . .”