Successful teacher

I recently read a book called The Devil to Play by Jasper Rees. It describes how the author masters (sort of) the French horn, after many years of playing the instrument in school.  I've never played a musical instrument, except the piano, at which I was supremely untalented.  I never realized how difficult it is to play the horn and how easy it is to play it wrong.  In the future I will regard horn players with wonder and awe, like mountain climbers.
I can't imagine doing something so difficult.  It's tough enough to sing in a choir, where there are lots of other performers to cover up your mistakes. It takes a lot of courage to face an audience, no matter what kind of performance.

There's also a lot on the history of the instrument,  and the literature written for it, which I considered fascinating.

This is by way of introduction to my main topic, which is how to be a good teacher. In the course of his book, Jasper Rees quotes reports by the various teachers who attempted to instruct him on the horn, and they are always very positive.  Each instructor invariably remarks on how much Jasper has improved during the course of the term.  At the rate he was improving, I'm surprised he did not become a famous, indeed a world-renowned, performer.

As some of you know, I take art lessons.  My art teacher looks at all the student work at the end of a session and invariably says something encouraging; the mastery of color has improved, this shape is well done, etc.  I am sure he sometimes teaches incredibly untalented clods, but you'd never know it by his critiques.  I guess teachers are in the encouragement business, not in the hopelessness business.  Tact is of the essence.