To the left you can see one of those pieces finished and colored ready for a page in that sketchbook––and in this blogpost I'll break down the process to get there (including a species swap)
Right off the bat you may notice that the rough is very different from my final. That's because the commissioner requested a mouse with a tiny badger almost like a pet spirit animal. This tied in with their own RPG character. I was totally fine with it, but explained that I would alter the piece digitally for when I published it for a sketchbook. The rough/layout started with two drawings: the mouse (with a requested mace design from Everquest) and the wee badger. I scanned both, tinted them and placed them in a square template before roughly blocking in some digitally painted forest floor foliage.
In addition to inking the beetle, I also needed to ink in any ground cover where the badger was.
I'd added a few registration marks around the patch piece (noting the mouse's eyes or the point of a leaf or two) to help me after I scanned it to get it back into the correct position. In addition to getting the new inked piece in an registered properly, I had to mask out the linework of the badger so it didn't show through anywhere––especially in the open white areas where it would be very obvious if I missed cleaning it up.
Once I had clean inks, I could start the coloring process for this piece. That first step is called 'flatting' which is basically a professional task of coloring-in-the-lines and establishing what color area each thing in the piece is. The final colors can be altered, but it's good to establish the distinction between the leaves and the twigs or the bark and the beetle.
I also took this step to establish a color hold (an area where I want the black linework to be a color other than black) on the background leaves to help push them back and add a sense of depth.
Here are the final colors all rendered and textured. I do most of this work only using two tools in Photoshop: Dodge and Burn. These are tools that date back to when Photoshop was a photo retouching tool and emulate part of the development process to over and under expose areas––ie: make areas darker and lighter. So with a stock textured brush I add shadows and highlights.