First suit head progress. Tips/redlines??

Posting for a friend. Meant to be a generic, GSD-looking canine. Bottom jaw's being redone.
Ref: http://fc05.deviantart.net/fs71/i/2013/212/c/7/hazzy_partial_concept_by_ayashekinz-d6g2nh8.png
Pics here: http://imgur.com/a/5NcH6#0

Any advice or tips are appreciated, redlines would be very helpful! Thanks so much!