modeling/sculpting is much a matter of practice. Good that you invested in an anatomy book. Well spent money. However with your model there minor adjustements you can do to enhance it and to get that comic-style your after.
When dealing with cartoony characters you can leave the proportions out of there, however anatomy is alwas a vital part of any organic looking model as long as you want it to look a bit like a human of course =)
Som minor adjustment you maybe want to try?
- Push his cheeks in and smooth it out
- Adjust the ears and make them more stiff and not so bumby, but i like that he got some thickness to them, Most people make ears which is more or less flat as a pancake =)
- The eyes(or the part containing them) works better if they are not rotated, so straightenn them out as well. and the nose might need som paint strokes and somesmotthing.
A good thing when smoothing and building up form is if you go up to let’s say subd 3 and make the adjustements and then smooth it out with intensity set to like 60% so it won’t push your model in undesired places.
Hope something of this helps.