Hello! This just a small guide for young/beginner artist.
It doesn’t matter what software you use, for me I primarily use Paint tool sai.
Mario is a good example of a character who has primary colors.
Patrick uses different variants of secondary colors.
Magenta’s color is tertiary because it is between purple and red.
Luigi has a analogous color scheme, color adjacent to each.
Yoshi dominant color is green, red is the direct color opposite from green.
Dipper’s shirt is the red, his hat and jacket serve as (indirect) split complementary colors.
There’s also Traidic color scheme: three colors equally spaces on the color wheel.
Tetradic color scheme: double complementary. (quite difficult to use)
And Monochromatic: variations of light and saturation of one color,
Value is the lightness and darkness in color.
This shows about 9 values. Value is important because it shows the illusion of light.
This is one of the mistakes a lot of young/beginner artists make. Unless the drawing is in grey-scale, black and white as shadow and light is wrong to use.
I use Luminosity and multiply, of course their are other modes to use, like shade for shading. screen or overlay for light. (paint tool sai user) light is not always necessary btw.
Never be afraid of using a warm color as a shadow and a cool color as light etc.
Always experiment with your art, try new things, and figure what’s best for you!
Let me know if any of this helped you, and thanks for reading!