Here’s a video with nice techniques for making a base with overgrown debris. The techniques also would come in use for modeling the floor of large terrain bases, such as tree stands.
Modeling
Making A Prehistoric Hut
Carmen’s Fun Painty Time blog has an article on making a nice prehistoric hut out of sculpy.
Techniques and Tips For Cardstock and Foam Board Modeling
Pulp Places offers a free guide with techniques and tips for cardstock and foam board modeling. The author writes that the free publication collects tips from other modelers, as well as capitalizing on his own mistakes.
Thatching Model Cottages
Here’s a tutorial on making thatched roofs on model cottages.