Jackie Musto just sent in the final images for our House of Paper Shadows adventure and she included a gif of the following illustration so people can get a glimpse into her process:
It is an image of life inside a tulou-style walled village. I won't say more because I don't want to spoil the module for people. But below is the gif showing the artwork's stages of development. Rather than explain it to you, see Jackie's note below where she talks about how she composed the image.
Jackie: A WIP of the village scene. I always start with a loose sketch to verify where I'd like all the elements. When I'm making up a composition, I try to keep in mind an interesting angle that will highlight all the specific characters or elements of the scene to keep the importance on them. After working up the backgrounds, I tend to make the characters on their own layers so I can scoot them around or easily separate them for inclusion on other areas of the book. Lastly, the most tricky element is keeping the contrast in check so the final illustration ends up interesting and easy to read!