I always remember my primary school teacher and one from the university.
The one of primary for its simple and way of giving us the classes was very didactic and dynamic.
And that of the university was very professional and prepared in its subject, it did not have excuse to explain something to us, always very collaborates and attentive to our doubts.

A great teacher is one who is always there to help and teach his students if they reproach them. and must be demanding in their tasks and acvies. First of all, be cordial and exemplary.