Draw a circle
Add a smaller circle in the center for the iris
Draw an even smaller circle inside the iris for the pupil
Add a tiny white highlight in the pupil or iris
Outline the iris with a darker ring
Sketch a few radial lines inside the iris
Shade the pupil dark
Lightly shade the iris
Add a soft shadow around the eyeball for depth
Draw a curved upper eyelid line over the circle
Draw a curved lower eyelid line under the circle
Add a thin outline for the sclera
Refine the edges and clean up extra lines