Adults have an attention span between 15-18 minutes so try to keep your lectures no longer than that at a time. Rehearse and practice your lectures before the class happens, especially new instructors. When ending class for the day ask the students what was learned, and you may provide what you think can be better. Lastly and most importantly, make sure to keep the students engaged with various deliveries, positive and motivating feedback, to ensure a healthy learning environment.
