Uhmm well I guess the basics would be that I work from the darkest shades to the lightest tints (usually between 5 or 7 colors) and the darkest shades should be a sort of greyed out red-violet color slowly working up to orange tints. as far as brush work I use the Opacity brush in photoshop (the one that becomes more transparent the lighter you touch) and just do alot of light layers to make smooth transitions.
I love the colors on this, and the blueish sparkle stuff is a very good addition! It adds a lot of light to the picture and very much gives him a classification of 'magic wielder' or something like that. Very nice job!