Post By waldronate
Just happened across this site... Terrain Models - Characteristics - Exaggeration That's the page I started on, which I found interesting.
If you go to this page: Terrain Models - Techniques - Plaster there is a link in the bottom paragraph to a pretty neat video on the process of plaster terrain modelling.
I haven't explored the rest of the site yet, but I'm sure I will.
Relief Shading is done by the same folks, but deals with general hillshading techniques. Shaded Relief – Home is done by a USGS artist, but is also relating to hillshading.