I would advise to read about the "chromatic circle" (or "color wheel", in proper english ?).



The color wheel is a tool for artists (not a representation of real light working !) to quickly create color schemes who will be pleasant to mostly everyone. (of course, because behind it, it's build upon how the human eyes and vision cells are responding.)



And then to devise " Color schemes". Easy and very efficient color schemes for example would be complementary colors (colors opposed on the color wheel, like blue vs orange, very often used in blockbuster movie because the contrast is very efficient between both colors)



here, you have the classic violet (Rarity's hair) vs green shoulder free shirt, you'll see green and violet are opposed on the color wheel, so it's a very pleasant combination to the eye.

You'll see that combination in many works, for example in Disney "Sleeping Beauty", a mostly green and purple/violet movie.



You can also create more complex color scheme, for example, by tracing a triangle in it, you could choose a three color basis for a picture : green, yellow and purple : You would add yellow with cautious (because too much of strong colors will confuse or tire a watcher). It's used in Disney Sleeping Beauty to add accents to Maleficient (her bird has a yellow beak of course, some parts of her garments and so on )



And so on.



it's a great tool to make color schemes which just works, as in Fashion. And it explains why some pictures are so "vibrant" or why you can see so often same combinations of colors.



Of course, it's just a rule. You use your taste and experience to break it or tweak it when needed.