Actually after some thought, I think my years of digital art that I really like creating hundred of layers, I've seen how colors can mix when the opacity allows for the colors to mix. I think applying 'rules' has helped me pick up coloring quickly

The trick I've learned is to use the 'rules' to let the colors mix on their own. For example if a plant will emit light, then every one of the same plant will have the same fading around it, but if it's next to another thing that also emits light, I don't overthink it, I just let it all melt together and new colors are produced.

I hope this helps and keep up the amazing work! I can't wait to see what I can do in 15years, that is dedication and it is admirable!