Creating concept art
Concept art can be almost anything. Crude sketches, fancy hand-drawn images, photos, photoshopped messes, and even simple 3D setups using cubes. Anything. All it must do is give you a general idea of what your scene is going to look like and what you want your final render to look like.
Why bother with concept art?
The idea behind concept art is that you can test out your ideas – any ideas that you want – with much less effort than actually doing it in Blender. It also gives you a good general idea of how you want your scene to look – some concept art might help you figure out what mood, colors, and more you’re going for.
Every major movie, every TV series, and every video game makes heavy use of concept art to figure out what things look like before they’re made. There’s people who create concept art for a living. That’s their job. In bigger studios, 3D artists don’t have to worry about concept art...