After the 1st day of a new group of students, you should should always approach each day with a mental plan of how to reach the days objective. You should always have a plan "B" just in case. Remember you are the guide and must steer the daily lesson to keep it within the "white lines" of the daily objective. Don't be scared to step on the "white line" once in a while to keep the students engaged. At the end of the course or semester the real goal is the students learning the material. the rest will usually take care of it'self.