Although I've used something similar I never really had a formal process for creating what Web Designer Depot and others call a mood board. I've had swatch files, inspiration files, and such but in Why Mood Boards Matter, Mindy Wagner offers up reasons how mood boards can help you when working with clients and how to go about creating them. Focused on Web design, the same principles apply to print design as well.
In addition to Mindy's words, I've gathered up additional opinions and tips on How and Why to Use a Mood Board. What's your mood?
Also see: Doing Thumbnail Sketches