Step 1: Ideate. This one worked out first try. There's a prevailing philosophy to never go with your first idea. The old dead artist philosophy was to do 25 sketches like this so you get a wide birth of ideas to play with and from an artistic perspective I agree with that. The first idea is rarely your most creative. But some ideas just hit the first time, and I rarely have time to come up with 25 different variations on the same theme that I equally think would be valid!
Step 2: Make that mood board! I know what all I'll be including. Just need to collect the textures and images I think would be best for them! Also take reference images!
Step 3: Colors! Make a new layer, darken the sketch layer, add a new layer below the sketch layer, and put your colors there!
Step 4: Mood setting and bg! So this is meant to depict the characters wet and also have a "chaos of the world melts away" kind of feel! So I deepened the colors, added some shadow gradients overtop the figure using purples and a multiply setting on the gradient tool, while the transparent pixels were locked (meaning I would only paint on pixels that already had pigment on it) For the bg, chaos is easily represented by an almost random smattering of colors and brush presets. Still debating on whether or not I want to keep the "no colors touching the characters" implying a "the chaos doesn't touch us" kind of motif.... I think it would look nicer if it was touching the characters.
Step 5: Paint the rest of the figure! So it all got away from me, updating this! But all of the fundamentals are there. Values to imply the light source, the colors I'd need generally, the form. Really all I did was detail it which has more of a personal touch. For me that's adding in colors that I think express myself better.