Practice and you will understand why your shading never looked realistic... There actually is a method. It was the term "little circles" that threw me off for years.. I thought it meant little circles on the paper...but no. It means the tip of ur pen or pencil will be making little circles onto and off of the paper. It can't touch down directly into the paper it must glide onto the paper like a plane on a runway landing...and taking off...cuz the pen must also leave the paper. Then you do this, it feathers the edge (beginning & end ) of your shaded line..so that it fades in and out.