I don't know what sort of things you want to teach about. RobynsVeil certainly makes some good points, and I would not disagree with her. DarkEdge also makes a good point, lighting is a weak point for many beginners.

However I'll mention a few other things. Many of them may not be relevant to the sort of tutorial you want to do, as perhaps some are a bit more advanced, but these questions keep cropping up in the forums.

Setting the display options for the scene, and particularly for the GROUND plain can be challenging for beginners. Also worth pointing out about Preferred state, and to UI dots.

IK, its uses and abuses is a must.

Having binary morphs turned on in the General Preferences is a curse, newbies should be warned about this.

Beginners forget about focal length, and don't realise that the ridiculously short default focal length is only suitable for panoramic landscapes.

The Body and hip. Beginners will translate the hip, then wonder why applying a pose moves the figure to a different location.

Spawning a morph, or exporting a morph target as an obj. Beginners don't usually understand what to include in a morph. They will for example use a magnet to make the nose longer, then spawn a morph whilst a character FBM is still applied to the head.

Saving a smart prop. That one had me stumped for long time. You can't use "Select Subset" if you want to save as a smart prop.

Animation. Worth pointing out that Animating can be turned off for lights and cameras, and that Linear interpolation, is often much more appropriate than the default Spline interpolation.

Some other questions that pop up regularly:

I want V4 to hold the sword (gun) in both hands!

How do I make INJ and REM files?

Walk Designer drops my figure to the floor, how do I make her walk on the roof?

How do I make a MAT pose?