you are suffering from 2d conversion issues.
I can tell this because your straight on face does have some good principles to mapping out the face (like the grove from your corner nose to lips) but your side view needs allot of help.
You see the 2D form, but understand the substance that holds the skin (bones) and where they poke through. You mission should be is go to a crowded area and start stareing at cheek bones.
Every time you turn the model Stop work on it and just ask yourself what would it look like at this angle?
heres a link to some great reference
http://www.houseoftutorials.net/Zfleamarket/index.php?album=Loomis-Books
But you must study people also or you will never understand 2d to 3d
Also cheat a couple times. Take a front and side head and place it on a reference plane and sculpt it.
Build up your confidence.