Before you even open your mouth to begin your lesson, your posture, body language, and expression are sending clear messages to students. They're drawing terrifyingly strong conclusions about your standards, how much you care about them, and what sort of expectations you're going to hold them to. The good news is that establishing good teacher presence -- the warm and demanding kind -- is a skill, not an innate quality. As is modulating that presence to meet the particular needs of different moments in your lesson.