For colors, I remember Tom saying that he likes to use colors in the middle of the color picker grid. Colors on the top and right are too bright, and when he does greys he never uses a stright-up grey from the far left, he always adds just hint of color, since almost nothing(especially organic stuff) is a pure black/white mix.
Another thing to think about is warm and cool colors. Warm = red, orange, and yellow. Cool = green, blue, and purple. Similar hues complement each other and blend well, while opposite colors contrast each other(which can be a good thing).
I could go on, and give you an entire lecture about color theory and design, as I’ve been learning (and remembering) a lot about it since I started work my color mod. If you have any questions about color, I am your guy to ask!
Also, @Pandemic recently posted a really helpful tool which you could play around with and maybe get inspired with.
Another tip I could suggest is to look at some color art of what it is you are trying to recreate (or something similar, like an ostrich or emu or maybe even a chocobo). Go on to google image and browse the pictures and see if you can spot any patterns.
But don’t get hung up on trying to make it too realistic! You can only do so much with voxels without it looking weird.
Edit:
OH! And another thing! try not to use straight solid colors, as they look bland and unnatural. Qubicle’s Noise modifier is a life-saver when it comes to this! Select a single color of your model and try it out on a low setting like 2 or 3 and see if you like it, if not, you can always undo.
I hope this isn’t too much info all at once. 