Right. What hes trying to teach you, still applies. your doll/cartoon looks really flat, and in reality, things of made up of forms in 3demsional space (well that how humans see it :p) Instead of making a paper cutout, you have to sculpt or "mold" things with shadows and highlights. If it wasent so flat in the first place, he would not of had trouble guessing what it was.
Look at the way he used the highlights to "raise" above his "eye" and better yet, the shading used to make the nose look like its raised from the face.
@sherman pretty awesome edit, you have been taking the time to help beginners a lot lately -including me- I thank you for that.