Kealios’ Wargaming Central has a tutorial on making bocage in 6mm from clay and craft sticks.
modeling
Modeling Birch Trees
Here’s a tutorial on modeling birch trees. Like palm trees, these are sadly very much underrepresented among cheap plastic model railroad trees.
Making Roads From Cork Tiles
The Wargames Table has a quick tutorial on making roads from cork tiles.
Modeling An Objective Marker
Dampf’s Modelling Page has a short description of how he created an objective marker. I really like markers like these that look like part of the landscape, as opposed to little cardboard counters or somesuch.
How To Make High Quality Circular Counters
On Board Game Geek, there’s a nice set of instructions on making high quality circular counters.