I started off this painting how I start any watercolor piece, with a sketch. For my sketch I used the real pencil and design brush (but mostly the real pencil). These are default brushes that come preloaded in clip studio paint.
I also keep my character sketch and my background sketch in separate layers.
For this step, I'm just laying down the base colors for the character and the background. All three color layers here, (the character, foliage, and sky) are all kept separate. I used the "brush set for drawing leaves" for the nature and the "(Ver.2) Color Bleeding brush" for the sky.
For this next step I'm basically just fully painting the background and character. For the Background I am again using the two previously stated brushes (brush set for leaves and color bleeding brush). I'm also using The Gouache brush (default) and then the Gouache brush set (from the asset page).
For my character I used The Gouache default brush, The Gouache brush set, and the Watercolor brushes in the Artist21 brush pack (which can be found on the asset page).
After this step I merge my character lineart and colors into one layer and repaint over it (like how i would for a traditional painting). I use the Gouache brush, Gouach set, Artist21, and artemus hard pencil.
Watercolor Paper textures
I used a watercolor paper from the "Watercolor Large Texture" pack over the background but under the character layer (the texture layer is on hard mode and lowered opacity). Then I use a regular paper texture from the "Paper Textures" pack over the character and background layer (that texture layer is on normal with lower opacity). and finally I used another watercolor paper from the "Watercolor Large texture" pack on my character's hair (that texture layer is on overlay mode with lowered opacity).
Here's my final digital watercolor piece.