How do you draw skin on a portrait?

well in a nutshell... this is how i do it; i start out with a light outline of the face, work on the eyes, than the nose than mouth. and in between doing each feature i shade the skin. when you draw a face always look at the shades and blending NEVER make bold outlines because that takes away the 3-D and realistic effect. focus on the shadows when you look at the picture and when you draw you dark and light and all in between shades on the skin. than after that you can take a drawing stump or tortillion or even a tissue and smear the pencil markings to smoothen it out so the lines blend together. oh and when you blend make sure you go in the direction the lines do if that makes sense lol best of luck! :)