I don’t really consider that all this qualifies as much of a “technique”.
- Lay down a base coat of Olive Drab (WWII or Modern) for US vehicles ~ Panzer Gray or Dark Yellow for Axis vehicles. (Rattle Can or Air Brush)
- Slather on some Future Floor Wax with a hobby brush.
- Apply wet decal into wet Future.
- Cover with more Future and allow to dry.
- Top Coat with Tamiya Matte Clear (Rattle Can) to kill any Floor Wax shine.
- Weather to taste using Shaders and Pigments. (Pastels)
- Done
Link to Easy weathering and aging tips using Washes and Shaders
and a “How To” on some ways of doing wood floor decking: