This fella took 4 hours to do on hot press watercolor paper with watercolor pans.
I lay down light pencil first then a light wash of color and then thicker details with some colored pencil and a tiny bit of acrylic for accents. Inking is then done with a 10/0 nylon brush that I've cut down to half it's original size. On mixing colors, I find that mixing colors on styrofoam plates works great and then I keep the (now dry) plates stacked up, so when I need to find a muddy or a flesh tone it's there. A few touches with photoshop and I'm on to something else.