Behaving well with the students (no e there) is certainly one important point, but I believe that the following are at least as important:
- knowing what the students are expected to do/learn/know
- understanding what it's like to learn the kind of thing we (as teachers) try to convey
- being able to put oneself into the shoes of a student
- being able to joke, laugh and despair with our students
- remembering what we felt like when we were our students' age (I would LOVE to forget that!!!!)