Gary Gianni is currently publishing some interesting drafts of drawings on his own website (see the links page). Based on this I will show the different stages of producing a Prince Valiant comic below. Displayed is the big picture on sunday page 3513. Pictures are reasonable big in file size, so it could take some time to load.

This first picture is the pencil sketch.

This second picture is the inked version.

This third picture is the coloured and final picture.