Head sculpting is getting a little easier. I can do eyes, mouth etc separately but they still look mutated when I put them together on a face. You'd think I'd have it after 3 years of practicing. Not quite yet.
Maybe I just need to go back to structures and flora/fauna.
Digital. Clay is much easier.
Quick practice. I can tackle a mouth on a dynamesh sphere to work on fundamentals. I saw it done that way in quite a few "lunch crunch sketch" videos and thought it a neat idea.
Like this one. 
Modeling a Mouth in Zbrush - (Speed Sculpting)
Modeling a Mouth in Zbrush - (Speed Sculpting)
Thank you for reminding me about polygroups. I neglect that feature and I shouldn't. The base head shape I can get down pat quickly. When I'm happy with the overall shape and move on to placing features
that's when things get ugly. Ha. I will try what you suggested.