I believe that if your know yourself as well as your strength and weakness, it would help you with confidence you need teach your class.

When entering into a classroom you as an instructor should be very careful of your mind set because as soon as you walk through the door all eyes are on you and students are reading you like a hit on face book. I guess what I'm saying is that anything that is not pertaing to the subject you are teaching leave it outside the class it could effect your teaching and the way your students respond to you.