How to pick better colors that suit the ambience of a drawing?
My colors definitely need urgent improvement, and I think one of my issues is that it's very hard for me to guess which colors to use depending on the mood of the drawing, so my color picking ends up being very... basic.
For example when I draw a natural scenery, I'll often have the tree trunks brown (although I'm sometimes making them more green or purple, but still), the leaves green, the grass lighter/yellower green, the bushes darker/bluer green, the dirt brown, the rocks grey, etc. I just don't know how to guess which colors to use if I want to create an ambience that isn't just regular white light.
For now I rely almost exclusively on layers, blending modes and color correction to help me give tints to my colors, but not only it's not enough, but I also want to actually be able to understand it and do it myself.
Attached are some examples of my art, first four drawings were drawn this year and the last one is 2 years old, but I don't think my coloring has improved much since then. I hate my colors, they feel either dull or over the top, they lack harmony, and you can tell I have no idea what I'm doing.
What can I do to improve on that aspect? I've tried looking at photos and art, but I'm struggling to understand the logic behind everything, the best I can do is copy it and... not be able to reproduce it myself later, since I didn't actually understand why the colors were that way.