"Colour" as a tool involves a few different bodies of theory.
The first is light and its behaviour in a scene. I would suggest reading up on light (
link), what happens when it bounces and how its colour changes. Playing around with 3D engines like Unity can be a great way to quickly experiment with lights and see how they affect shadow and object colour (
video).
Particularly the matter of ambient light from the sky, bounced light from the scene and scattered light from the dusty air are elements that were central to the edit I performed.
The second aspect is mood and composition. Colour provides cues for warmth, emotion and energy, so knowing when to "cool" or "warm" your scene's colours, or when to "excite" or "relax" your scene with colour can make a huge difference to the conveying a mood for the scene.
Unfortunately I cannot really point you to good resources on colour psychology. Perhaps someone else can jump in. Googling "colour psychology" could otherwise be your starting point.
The third aspect is contrast. Neighbouring hues will have differing levels of contrast to each-other depending on how distant they are from each-other on the colour wheel, with complementary colours having maximum contrast and "excitation". Different hues also have different brightnesses, with yellow being the brightest and blue being the darkest, so as you change the hues of your shadows you need to tweak the value of the colours to keep the contrast of your scene the same.
I hope that helps give you a basis for colour.