Honestly, I have no idea how to explain it. I just color-pick from vectors, then shade with a darker, altered color (like AJ actually has red shading, and Rarity blue rather than dark orange or grey). After that, I just mess around with Color balance until I get colors I like.
Well, it's just that your style seems to have created this really excellent oil pastel (as in the implement) effect. So I don't know if that's your coloring technique or are you doing something else as well?