I stated with a rough pencil sketch then inked it with a brush pen and colored it with watercolor and gouache on a watercolor postcard. Reference I used was this excellent photo - https://www.pexels.com/photo/tree-wild-squirrel-monkey-97827/ photo by Mike from Pexels.com
I look at way too many carefully decorated spaces on Pinterest, so I painted one of them and then opened up the room to nature. Also a way to experiment with "gouache painting" in Adobe Fresco.
Practicing with reference: https://www.independent.co.uk/news/science/a-cats-level-of-aggressiveness-could-depend-on-its-colour-say-scientists-a6707731.html