Itīs really nice to see this! But actually, the mystery to me is still the step between 1 and 2 It looks already done! I always struggle with those first colour selections.. But, nonetheless, it looks amazing!
First I just block out the different areas (skin, clothes, hair) on different layers, and then I do very rough shading to get the right colour in the right areas... And I was using a colour reference for this, I didn't simply make up the colours.
I mean, often I DO sort of make up the colours, but to get to a point where you can do that, you need to look closely at photos and art, particularly ones where you can see the detailed progress of colouring it, and see what colours are REALLY there, rather than what your brain thinks is there.