Awesome - The main thing that you want to start thinking about is not what is 'best' or 'right' - but what is the proper design to illustrate an abstract thought - or human mood.
The best breakdown I have observed to is the pdf series by Clint Cearly. I am not him, nor am I associated with him. It is worth the money - and you dont have to scrub a video. Put the text into AI and break it down simpler if you need too.
Clint Cearly - Understanding Mood series.
The basics for color are already highlighted in the previous post - but this is the source for designing color's in a simple way based on the metrics.
Lighting
This is his book on lighting which I highly recommend if you want to start doing full illustrations, OR just lighting your character art.
Turns out we just use different versions of four lights - and also light with mood.
Color
This is his book on color. The metrics, the schemes, the pallets. It is also a data base -and a bit of a word salad- about each color ( i recommend skipping that section - and going to the schemes and pallets- and just using the cheat sheets when you need them.
Videos
Nathan Fowkes--
--is a concept artist for animation and games, working with DreamWorks, Disney, and Blue Sky Studios. He teaches color and light at Schoolism.
These videos helped me understand color relativity - and its application.
"The (Not) Rule of Color Temperature" - by Nathan Fowkes
"The (Not) Rule of Color Relationships" - by Nathan Fowkes
Winged Canvas - Jessie Chang
This video has many color pallets and examples that I had never heard of before and got me started on the idea behind designing.
"10 Colour Schemes You've (probably) Never Heard Of!" - Winged Canvas
That should be enough to get you started on your color journey. Break it down into steps until you get each chapter.
Here is a quick guide - to coloring characters.
Choosing colors for a character is about matching their personality and story with colors that feel right.
Think about their personality
Warm colors feel energetic, bold, or aggressive. Cool colors feel calm, mysterious, or intelligent.
Pick a color scheme
One color creates unity, similar colors feel smooth and natural, and opposite colors feel bold and striking.
Use colors in different amounts
Main colors dominate the outfit, secondary colors add variety, and accent colors highlight small details like glowing eyes or accessories.
Make sure they stand out
If the background is dark, use lighter colors. If the background is colorful, use simpler tones
Colors can tell a story!
A villain in dark purple and green feels eerie. A hero in bright blue and red feels strong and confident
Best of luck - Ta for now!