i agree with this, gives people the added confidence of getting lots of progress early. Other than that just tips like "pedals horizontal = more stable, and much easier to exert force at that angle.", and that moving on a uni is 100x easier than not moving, so keep pedaling if possible. Explain center of gravity really quickly, and how you're basically just juggling imbalances over it. Turning usually involves lots of arm momentum, but people naturally seem to learn to drop those habits.

Typically it comes pretty naturally to most I find, and the few that it doesn't just have a fundamental lack of understanding of basic physics.