Do you know how to either draw or use Illustrator?
I'd prefer to draw something like this in Illustrator. It does appear to have some painterly qualities, but I think you could get super close in AI. Then in the end, you could use the vector as your subject in Photoshop for finishing touches.
You could do everything in Illustrator, but then you're getting into more advanced tricks and additional layering.
It's just really nice to have vectors, when possible.
Looks like you could use 4 or 5 colors.
*Please remember to Rate our replies or check Solution if solved. If you get a good idea from the post, consider clicking the Kudos option.