Simple Atmospheric Perspective
Firstly, I use a perspective grid brush to draw a simple one point perspective.
Next, I painted the sky and the ground. This moment I had no idea what I was painting, I just painted what I think a landscape should acquire.
Then I added some mountains in the back, with lighter grey to make an illusion that they are far away.
With darker colors, it makes an illusion that the rocks with darker color are more closer.
Then, I adjusted the values using Curves, and continue painting.
With the Color blending options, I added some colors. But the values still looked off.
So I adjusted the values using Curves again.
Final:
