Do not assume to be the smartest person in the room. Even as an expert in the field, there is a chance that there is someone smarter in the room with you.
Be passionate about the knowledge you are sharing. But do not try to impress or prove your expertise in the subject.
Have a professional development plan. Continue to learn and grow not only for personal growth but to provide the latest and most accurate information to your students.
Model, manage, motivate.