I love creating an atmosphere of intellectual safety in the classroom by disarming normal student apprehensions: peer judgement, incorrect answers, penalties for different attitudes.  It allows me to gain their trust as an impartial mediator of the content.  Equally important to my efforts is to have a clear message for the lecture, which is especially important when an active discussion happens with the class.  I find that I spend a lot of time trying to distill my message as much as possible to make make message have a greater impact and to give more time for discussion.