Hmmm, commissions are a tricky subject. I will do commissions, but NOT pet portraits. When I was younger and starting out, I did a lot of pet portraits. People would give me a photo of a dog standing in a field and expect the spots to be perfect, when I could barely find the dog itself. What most people really wanted was an enlarged photo, so they should just go do that.
The sort of commissions I will do have looser guidelines. For instance, a lady wanted a painting of a squirrel that included the colors blue & pink. I painted a grey squirrel in a tree full of cherry blossoms against a blue sky. Another lady wanted a painting of a particular bird for on her sailboat. I painted the kestrel hovering in the sky with said sailboat in the distance. Those are the kinds of commissions I'll do.
Having said that, I must warn you to allow at least 6 months for the commission to be completed. Health reasons cause me to work at a slow pace so it takes a long time for any painting to be completed. Commissions add a lot of pressure, which sometimes has ill effects. I know all this sounds like a Diva, but I know myself well enough that I accept my limitations.