The only way I know to do this is by being a continual learner. As long as I am growing, my teaching will be fresh, since I will have fresh perspectives to bring to it. In contrast, if I am not growing, then I will not have enthusiasm for the material, and my students will not either. In an academic setting, one of the best ways to be a continual learner is through research. Research gives the teacher the opportunity to make new discoveries, and discovery keeps the learning process alive for the teacher as well as the student.
Effective teachers care about their students.
Teachers impact more by their character and commitment than by their communication. Most of us have had at least one teacher who knew the material well but showed little interest in his students. In my opinion, such an attitude misses a teacher's broader responsibility - to teach students how to think and to prepare them for life after graduation. It is easier to produce students who can answer exam questions than to produce students who can think independently and critically. Because of this perspective, I chose to work in industry before pursuing a faculty position.