Teaching art is very different than teaching technique. Teaching technique is what mostly parades as 'art' teaching in the contemporary art 'academy'. Teaching technique is grounded in an intellectual/analytical approach to art. Teaching art, however, is more the guiding of the student into their own intuitive nature or 'voice', so that the student becomes his or her own 'master'. This approach is a soulful path. It requires a profound receptivity and surrender. This receptivity and surrender is the ground of the joyful or ecstatic path of the artist. It is a non conceptual path. It is the path of originality.
Now, this commitment to the joy of self expression is the Teacher. It is life energy (or prana in yogic terms) informing the moment to moment expression of the medium in relation to motif. One must surrender to some degree the will to the intelligence of the life energy. There is joy connected to this surrender. This joy is the quality of the self expressing directly. Once connected and committed to the joy of self expression, one learns to listen to and for this inner/intuitive voice. One's voice then evolves. One's style evolves. Each work teaches and furthers the process. One truly has become one's own teacher. What brought joy today may not bring joy tomorrow. There is this natural leading oneself further along. So copying oneself becomes less of an issue.
A human teacher is able to point out the direct beauty of the medium and keep the student on this path of direct expression.