I learned about using color blocking in character design, if you don't really have an idea in what they look like but have a general idea on their main color you can just put a bunch of colors in place and get both the color scheme and their appearance done at once. It doesn't take very long either.
I probably could've explained it better but I'm just saying as someone who struggles with color schemes and like making characters this is very cool.
(Also medi reset right when I exported my final design so I lost the sketches, I'm lucky I got it in time TvT)
Reference: https://youtu.be/A01M6vrGwJI