Hey Downwind,
Once you've set some aims, objectives and a motivation I usually ask students questions about the lift formula, and production of lift (from S+L). With the students participating in this discussion, because students are able to identify that as angle of attack increases that lift also increases. This often leads nicely into the brief when you continue this and discuss how lift only increases up to a point (critical angle) and then decreases - the stall. Simple introduction!
Its great when revision of a topic already covered leads in to the briefing being delivered. allows students to go from the known to the unknown and gives previous lessons meaning and purpose! All a part of the bigger picture!
Enjoy the course!
Mo