I tried to take the best methods from the miniature wargaming community and a few extra touches from the scale modeling community to add a bit more interest.

1. Prime Black Primer
2. Basecoat US Olive Drab , highlight with Green Brown
3. Apply decals
4. Wash bottom and track areas with 50/50 Muddy Brown and water.
5. Paint bogeys with German Camouflage Black Brown , or some other dark brown that looks like rubber...
6. Paint tool parts Leadbelcher (or any Gunmetal color), base wood handles in White and overcoat with Snakebite Leather
7. Paint Treads Leadbelcher . Wash with 1:1:1:1 mix of Pure Black , Muddy Brown , Typhus Corrosion and water. Paint road wearing surface of tracks bright steel (I used Silver RLM01 Metallic ).
8. Varnish
9. Add Dark Streaking Grime and Light Rust Wash as desired
10. Varnish