Leaving It Out
I've come to believe that a key factor in any class is what is left out. If too much information is included, that can dilute the impact of more important material and become a source of confusion.
"Too much information" is especially tempting if you love the subject. You want to tell them this and that and, of course, the sin is fostered by the fact you are approaching the presentation from the standpoint of what you enjoy rather than what the audience needs.
What they truly need should be your guidepost.