New instructors almost always over-plan, then rush the most valuable part: the time students spend working with the material. Estimate how long each piece will really take, then cut your plan until practice and questions fit comfortably.

Build in slack. Mark one or two segments as optional so you can drop them if discussion runs long, and have a short extension ready in case you finish early. Watching the clock is not rigidity. It is how you make sure the class ends on the learning that matters rather than on a slide you did not reach.