Taking notes
While at our core we are artists, I would argue that our primary job is as a communicator. Surely, painting is visual communication, but you should never overlook the sheer power of words to convey an idea. For every one of my clients that require preliminary sketches or "value passes" (such as card art, tabletop roleplaying game art, and concept art jobs), I always send in a draft with notes not only in an email but also embedded in the art file itself. These can be either handwritten or typed using the Text tool, but no matter the method, I want to make sure that my client can follow my train of thought, or see questions I might have for them directly relating to the piece.
I've heard from a vast number of my art directors that they love that I include notes, as it helps them relay information to their team, and saves everyone time (and about 20 emails) in the process. Saving time saves money for companies, and if you're a skilled artist that also...