Here is a picture I did of the lovely Stephanie Hudson. I used a grid to draw from a photo, and colored the whole thing in Photoshop. I primarily used the dodge and burn tool, this is one of two major methods I use (the other involves painting in colors for the highlights and low lights). To make the skin more realistic I duplicate then merge the entire picture, then change the layer style to dissolve and adjust the opacity until it’s a nice scattering of colored dots. Once I have the dots right I duplicate the layer then merge the two (this rasterizes the dissolve effect), and blur and erase until it looks realistic. As usual, the top layer is the only layer that contains pure white, this will intensify the effect of bright reflections (like in the iris). Below are the pencils for this piece.