Hi, I often make up some swatches for each individual piece of work. Often use colours from the reference photo or alter the colours if, as in this case, want an overall different look. As I progress in the painting, the colours are often picked from the work itself rather than swatches.
Over 2013 when I began really getting into Digital art, I've moved from straight copying a reference photo, to painting it different. I'm still working on getting to the stage where I can do a photo-realistic painting with no reference whatsoever... Now that would be a challenge!
This was very helpful! I combined some of your tutorials with some others as I drew Ellen Page and it turned out soo great!! Thank you soo much for sharing! If you're interested in seeing the result this tutorial gave me, the pic's on my page ^^ <3