Drawing on material from pre-requisite courses
I like to incorporate material from previous courses in the curriculum whereever possible. By asking questions that relate to both current and previous coursework, it reinforces with the students that one course builds upon another and also is a great motivator to show them how much they've learned already.
I teach a class that comes near the end of my students' schooling and I do this as well. I find that it helps build their confidence levels with the new material when they can see for themselves how much they've already accomplished.
I work this just the opposite. I teach courses that are mainly the beginning of the student's college career and if needed, work into the class work an explanation as to why they need to learn this. Most of my students at one time or another do ask the "why do I need to know this" question.
