After scanning my ink drawings, I opened them in Illustrator and used the Live Trace function to turn them into vector art. I then brought all the vector elements into InDesign, mixing and matching one drawing with another, to assemble the designs.
I scanned in pages from West Elm and Crate and Barrel, and I used InDesign's eyedropper tool to create swatches of colors from the images. Then I tested out various background colors for my patterns using these color combos.
Here are some of the final patterns, as mocked up in my Society6 shop: