This video offers a useful method for making a realistic stone texture on your models.
modeling
Making Sagebrush Trees
Ryan Scow has a tutorial on making miniature wargames trees from sage brush. They are very good looking.
How To Make Balsa Look Like Timbers
Ryan Scow has a tutorial on how to make balsa strips look like timbers for use in models of half timbered houses, stairs and other miniature wargames terrain projects.
Making Ocean Terrain
GHQ, maker of those fabulous microscale armor and ships has a tutorial on making ocean hex tiles. The techniques also could be applied to other terain forms, such as those large styrofoam squares so many seem to use.
Building Desert and Martian Terrain
This video describes how to build some terrific looking desert and Martian terrain.