The first impression students have of you is your appearance. While there is no University dress code, your department may have explicit or implicit expectations for how you should dress when teaching. Even if you have complete freedom in this matter, it is a good idea to think carefully about what you wear. Casual clothing emphasizes your accessibility to students while more formal clothing emphasizes your professionalism. If you feel doubtful about your ability to command the attention of your class, professional dress may provide just the ego-boost you need.
Many teachers start with more formal dress and go to more informal clothing as the term progresses.
It is important to remember that initial impressions tend to be lasting and that the way you choose to spend the first day of class will set the tone for the entire quarter. Rapport A light touch is golden at the first class and interjecting your own brand of humor will help get things started. Be careful of jokes, cartoons, or comments that could be interpreted as racist, sexist, or homophobic. Remember that as their instructor, you occupy a position of power in the classroom. It is very difficult to establish a positive teacher-student relationship with students who feel that they are not welcome in your class.