This one was interesting to do since it was an oil piece.
My notes on color and color mixing are only based off what I have learned so far... which isn't too much (so take it as a suggestion). Color mixing is something that I am working on right now, and it is an extremely dense topic. Lot's to learn. So I tried to keep it basic.
Cadmiums dry incredibly slow. I used a cad orange in a still life study, and it took a couple weeks to dry completely--and it wasn't even very thick.
Slow drying times can be problematic... because sometimes you need the paint to dry before you can start adding more paint and/or new color.
And I cannot stress this enough... but: VALUES Always make sure you have correct values. The lightest lights, darkest darks and the midtones in-between need to be established before anything else. Value is light. You need light before you can have color--literally. This isn't an arbitrary rule, it's optics (aka physics.)
If your values are off, it doesn't matter what colors you choose, it will look wrong. Nothing can save you from poor distribution of values.