In October's issue of ASCD's 'Educational Leadership' there is an article on mastery learning. Whatever the merits of that particular approach, there were a couple of statements in the article that apply to all excellent teaching, whether in the classroom or beyond:
In mastery learning, teachers ensure the conditions for success before instruction begins.
In mastery learning, assessments are not a one-shot, do-or-die experience.
These are good reminders for all teachers.