I finally got around to finishing this. Thanks to Scott, Hamish and Maciek
for feedback. I've incorporated everyone's suggestions into a final draft
which I've uploaded to the WIKI on the Development page:
http://grass.gdf-hannover.de/wiki/Development
Direct link to the 'Updating Grass Documentation How-To':
http://grass.gdf-hannover.de/wiki/Updating_Grass_Documentation
Everyone can make edits to it to improve clarity, formatting, etc.
Hopefully, it will be useful for those non-programmers who want to
contribute to improving Grass.
Cheers,
~ Eric.