Hi, Thanks very much!
I work 100% digital from start to finish, using Photoshop and custom brushes. On the softest pieces with a lot of line work, I draw the lines and then add color. For the more heavily painted looking pieces, I usually have a rough sketch and then start immediately roughing colors and refining them until the end result. Recently (like with the Giles covers), I've been painting in black and white, making a full render…then I use a gradient map to apply an overall coloring, with some additional layers of spot coloring using the blending mode. That's a very general overview, if you have a specific question, let me know.