First I start with a very small thumbnail, searching for an interesting composition that will tell a compelling story. Even though this is just a small color comp, take your time because this will be the foundation for your entire design. Be sure to zoom out at this stage so that your canvas is very small on your screen. This way you can pay attention to the overall composition, the big shapes, and the organization of the elements, instead of getting caught up in the details that we will address later on. As a general rule the 3 things to think about that will determine the outcome of your piece, in order of importance are:
Next, I overlay a line sketch to design all of the individual elements, focusing on correct perspective, dynamic lines, eye movement, and focal point. Once you've decided the story you want to tell, the question is how do I utilize everything in the piece to reinforce that story?
Value structure is important so if a piece is complicated with a lot of layers, it's a good idea to do a black and white study of the basic value structure, deciding how you want to light the painting. In this piece I went with a typical dark foreground, medium midground, light background.
As I'm designing I will constantly flip the canvas horizontally, which does 2 things. It gives me a chance to look at the piece with a fresh set of eyes, and in doing so will also help me to see any perspective issues that need to be corrected.
A general composition rule is to divide your canvas into thirds and place your major focal points at any of those intersections. Outside of those intersections, your composition can arguably become flat, less dynamic and promote less eye movement.
In this composition I decided to use a very fluid form language, with the shapes of the rocks guiding the eye in a circular direction, never leading off the page, but rather inwards toward the focal point. Regardless of where the viewer's eye enters the canvas, and what direction it travels, the lines will always direct towards the area I designate as the first read. Further I will choose a second and third read and be sure to develop these as "mini compositions" within the page.
From here I overlay my original color comp as "color" under layer properties. What this does is transfer my original color intentions, but now with my newly developed value structure intact.
Then I will start to define the 3 dimensional shapes I have drafted, making sure to follow the light logic I established early on.
With the sun setting beyond the horizon, light has to travel through more dust and moisture in the air, thus turning the sky more red and yellow. My highlights on the ground will be warm reflecting the little light that is left in the sky. My shadows will remain cool, and less saturated.
I add smoke to the scene to provide more atmospheric perspective, depth, and movement.
Only when I feel the overall composition is working will I start to add details. Adding lights to the man made structures will help provide the viewer with a sense of scale.
Towards the end I felt like the background structure needed more contrast to draw the viewer's eye in. So I added highlights indicating the sun direction. I also felt the background wasn't dark enough given the low sunlight, so I darkened the rocks. My last layer is set to a "hard light" under layer properties. Then using an airbrush I paint in a glow around the highlighted surfaces, reflecting the light into the dusty air. At this point I feel the piece communicates the story, mood, and visual language that I originally sought out to accomplish, just enough so that it does not feel overworked.