While I admit it is a different mind set painting miniatures, the techniques are the same to make it look realistic. No matter if it is a figure, a plane, tank, car, etc, etc. The techniques are all the same.
Making an armored vehicle look like it is used in the field with the mud and dust, lighting and shading to me is no different that doing the same to a figure. No matter if it is a 1/9 bust, 120mm figure, 1/35, or 28mm....techniques are all the same. If anything, it is hard to achieve on a larger figure or bust in the 120mm or 1/9 range than it is on a small 28mm figure, because there is so much more detail in the larger figures to work with.
To me it is all an art form. Those that can get an ultra glossy, flaw free finish on a car, someone that can create a realistic looking tank, weathered aircraft or a figure....its all a form of art in one way or another.
Being one that builds pretty much everything, I use alot of the same techniques and ideas no matter what I am building. I am currently working on a 1/25 Truck and log trailer, but I plan on weathering it with rust, mud, dirt and dust like I would a tank so it looks like something that looks realistic and used in the woods instead of coming off the showroom floor.