How can I give my sky greater depth?
It’s easy for the sky in an image to take on a twodimensional quality, where it appears to be one large, flat volume. While this may be suitable for some images, sometimes it’s advantageous to be able to accentuate the perspective and illusion of depth in your image, through the sky as well as the ground.
A useful way to help push your sky further in Photoshop is to leverage layers and use the Transform tool. By constructing your file in such a way that the sky is in a separate layer, you can apply either Warp or Perspective to your sky from the Transform tool menu. By tweaking clouds, or any other volume you have in the sky, you can establish a base perspective you can then paint into.
It’s worth keeping in mind two other rules of thumb: atmospheric perspective applies to clouds as well as the ground. Clouds become more blue the further they are from the viewer, so having more than one colour in the base gradient you use for your sky is advantageous. Take a look at a blue sky: there’s more than one colour and tone at play.
Reducing the detail in your sky towards the horizon line reflects how our eyes interpret detail at a distance and also helps your image be less busy.
Layering one body of cloud on top of another is a great way to suggest volume in an expansive outdoors scene.