Set the example. Remember that you are the teacher. It is important for you to be like a "superhero" figure in their eyes. Remember that your students look up to you and will thus try to mimic your dispositions. If you are rude or inappropriate, they will have an inappropriate model for their behavior. It is vital that students see you as a person with confidence, so that they follow your lead, and feel comfortable trusting you. Students, of all ages, need someone they can lean on, look up to, and be able to trust.