I recall that my workshop leaders were tactful in their ways of acquainting me with my shortcomings as a writer. So much so that I hardly realized they were doing it. I want always to keep that sort of thing in mind when I'm teaching. The way you get better in everything in this life is to make mistakes. Otherwise you're probably doing it right by accident. But you have to do everything wrong before you can really start with some authority to do it right.