Keep a personal memo book on your desk open to the appropriate date. A calendar pinned to your bulletin board or taped to your desk top can keep you on track for long range goals. Time limits must be set ahead of time for your units, or you will not finish your units by the end of the semester. I realize there will always be situations that disrupt your plans. Grade XII students alone are often called out for presentations or graduation concerns.
Some classes require more time to get through a unit.
You must work on planning goals. Students cannot concentrate for long periods of time on any one given topic. Indeed, we know that the brain learns best in short bursts of concentration. An hour is a long stretch for students, and the desks they are sitting in are not really designed for comfort. I have always found that dividing the hour period into sections, and using different approaches works best.