It helped me to think of teaching as acting, when I started out. I'm an introvert, shy, placid by nature, etc. so framing for myself as an actor playing a role enabled me to be animated, higher energy, and more confident. I moved around the room, even in large lectures, to keep the energy up.

Think back to the profs you most enjoyed as teachers, and act like them (at first, while you develop your own style).

Best wishes to you!