Here’s a nice tutorial on making trees from bottle brushes.
Modeling
Making Magnetic Movement Trays
Mitch’s Wargaming site has a neat design for magnetic movement trays. I like the irregular shapes.
Dressing Up Your Tree Bases
The Wargames Table site has a tutorial on dressing up your tree bases
Casting Polymer Coins
This tutorial is on casting prop coins from polymer, but on a more miniature wargaming theme, I see this as a great way to cast casualty and morale markers.