I sketched and inked this drawing in my sketchbook, then took a photo of it to get the paper texture and some varied lighting. Then, in photoshop, I fixed some faded parts, edited out some bits of pencil and ink from the neighboring drawings, and turned the original drawing to a multiply layer. I colored mostly on layers beneath this layer. For the final touches I painted overtop all the previous layers and added the white outline + starry details.