Reddit mentions of The Artist's Complete Guide to Drawing the Head

If you havn't already, get a good book - i like this one.

Great start dude, well done! The one thing that a lot of people get wrong is the eyes. My advice, would be to practice each feature in isolation. Do lots and lots of eyes and then noses and then mouths and slowly build up to putting it all together. The best book I have read that deals with portraiture is this one:

http://www.amazon.co.uk/Artists-Complete-Guide-Drawing-Head/dp/0823003590/ref=sr_1_1?ie=UTF8&qid=1450195911&sr=8-1&keywords=drawing+the+head

This is the book I keep going back to. It deals with anatomy, but it also deals with shadow placement and other techniques, so you will see quick improvements. I found drawing people very disheartening until I read this.

Keep up the awesome work!

I've actually not read too many books on the subject, but I got this one a few years ago and it might be worth a look: https://www.amazon.com/Artists-Complete-Guide-Drawing-Head/dp/0823003590

What he's mainly teaching in that book is chiaroscuro, or how to model the form through light and dark and an understanding of how those principles work to create volume. He does have some valuable advice on understanding the structure of the face itself. It's not a holistic book by any stretch and I think the title is a bit of a misnomer, but it might be worth a look to learn about one particular method.