I first started with some black and white value studies just to find the major shape language and basic composition. I am not worrying about details at this stage just brainstorming.
Once I've explored a variety of value studies I picked my favorites and added some color as well as a little bit more details to flesh out the idea and story. If the painting is built off a strong thumbnail then I won't be worried about how it will turn out after hours of polish.
I decided to move on with "A" and began to work out the design of the building and props in 3D. With this I can accurately arrange my design in 3D without sweating scale, perspective and overall consistency.
Now I polish the painting and flesh out the idea with photo textures and brushwork. Here in this stage I remain loyal to that original thumbnail and with the 3D block mesh create a more accurate depiction.
and the finish!