The color studies with ink left me wanting to proceed from a different angle and make real progress, so rather than continue with gouache studies, I decided to jump right in and develop the composition in pencil.
First, I want to delineate the major forms to see how they fit together, as if they were pieces of a puzzle. Second, I want to focus on the textures in the arrangement of the building's broken stones, which I find the most interesting part of the image.
It's just an underdrawing, so a basic set of 6H, 4H, and HB (no. 2) pencils will get the job done.
This stage always ends up being more grueling than I expect, because of the patience required to get all the proportions correct. But at least for now I can still use an eraser.