The cotton ball explosion marker is a staple of miniature wargaming. The Miniatures and Terrain blog has a fantastic looking version.
Photos of China circa 1912 in Color

As the owner of a large number of Boxer Rebellion figures, I appreciate these photos of China in color circa 1912. My guess is that this is pretty representative of China over a long period of time, and will be useful for gamers from the Opium Wars through the revolution.
Modeling Wooden Road Obstacles
The Miniatures and Terrain Blog has this tutorial on modeling wooden road obstacles.
Modeling Wood Stacks
Here’s a photo tutorial on making some nice looking model wood stacks. Useful stuff for battlefields across the centuries.