One of the most important aspects of any set in animation is the fact that it should work as a stage for the characters and story, as well as any action that takes place within it. Animators set design should be no different: it should first and foremost be designed for the camera and story.
As a visual development artist, a large part of the job is being able to visualize what the film could look like aesthetically, using techniques such as lighting, texture, and stylization to get that vision across.
When you begin to design a scene, you need a simple story first. The simple story can provide enough context to get going on a set.