Paul has posted a photo tutorial on his methods for scratch building a Roman Town.
Modeling
Modeling Alien Trees
Dropship Horizon has a good idea for turning pine cones into weird looking alien trees.
Making Flight Stands from Q Tips and Spaghetti
I once built a series of 15mm south east asian huts from spaghetti. I have never lived that down in my gaming group.
Here’ is a set of instructions for making adjustable height flight stands from q tips and spaghetti.
Making Warp Portals
Warp Portals should be useful for a variety of science-fantasy games. Here’s a simple but effective technique.