I will use a quote I posted in a thread before, and I think it fits this topic perfectly...
Bruce Lee: On adapting to each student
"I believe in having a few pupils at one time as it requires a constant alert observation of each individual in order to establish a direct relationship. A good teacher can never be fixed in a routine... each moment requires a sensitive mind that is constantly changing and constantly adapting.
A teacher must never impose this student to fit his favourite pattern; a good teacher functions as a pointer, exposing his student's vulnerability (and) causing him to explore both internally and finally integrating himself with his being."
Throughout your life advance daily, becoming more skillful than yesterday, more skillful than today. This is never-ending. - Hagakure