Digital Illustration: Coloring

 Reference:

Selecting and separating the lines off of the background:

Adding green for me to see the colours clearly:

Adding the base colour of the skin:

Adding the base of the hair, eyes, and lips:

Base of the Orb:

Base of the Gold plating:

Base of the Clothes and Belts:

Base of the Staff and Gems:

Base of the Cat:

Base of the Border:

Shading the Skin and Clothes:

Shading the Gold plating, lips, gem and Staff:

Adding shading to the cast and highlighting the painting:

Shading the border and recoloring the background to fit the tone of the painting:

Final Output: