I agree with Judith that the pupil should be central in a teacher's mind:

A good teacher has a keen eye for each child’s needs. He or she should always act in the interest of the child’s intellectual, social, and personal development. A child should be helped to learn to  understand and work with the concepts of the subject field, to learn working together with peers, to know society’s needs, to build self-esteem and to know their own abilities and preferences… and much more!

This means that a good teacher treats different children in different ways: for one, with more emphasis on academic skills, for others who need it: with more emphasis on for example learning to learn; stricter when a child needs such an approach, more helping when needed; some students are being prepared for an academic career, others for a more practical job, some learn by doing, others by thinking… these differences should all have a place in a good teacher’s class.
Besides looking at the child’s needs, a teacher should also do this in a sustainable way for himself: spending time on improving lessons is only beneficial to the extent that the teacher’s physical and psychological health are not damaged by too strenuous efforts.

A good teacher is never cynical about a child, preferably maintains an optimistic atmosphere in class, is interested both in his subject matter and in children, and tries to give a positive image of being a teacher towards others: it is a complicated and challenging job, but also an important and fulfilling one.

Perhaps this is the discription of an 'excellent' teacher, perhaps a 'good' teacher needs to meet these standards only 80% of the time.