Embrace the imperfections, sometimes we design a "perfect" lesson and it does not work out the way we planned. Think quick on your feet, keep the student's engaged and be a role model that shows students that mistakes make us better, because we learn from them. If everything went according to plan the world would be black and white, imperfections just add a dash of color. This shows our students that it is alright to be wrong, sometimes it is necessary to have multiple versions until you find one that works.