Usually, I abandon a picture before I finish it, most of the time is because of this: if I don't like how the face is coming along, I don't bother continuing the sketch, so I spend a lot of time on just the head, face features and expression alone. Sometimes angles can be confusing, so in the end, I had to come up with a little guide to help me place features where they belong
First I start off with the basic circle guide with the lines, this shouldn't be new to anyone. I use the lines to help me place things later on depending on where the character is going to face. I don't use them to place anything specific on a specific spot, since that has led me [personally] to many different results, and I'm looking for consistency.
After I have the basic idea down, I add the face silhouette. First I simply go by drawing a line to help me depict the cheek bones [red], I then connect it in the perspective the head is facing, so I know how the rest of the face elements go. I then draw the jaw line [blue], using the cheek bone line as reference to how it should connect.
From there I add the nose first, for some reason, I find it easier to place eye sockets, eyebrows and lips AFTER I place the nose, otherwise I get easily confused.
It's just adding the details after that. Not too happy with this, but I'm trying to go for a simplier, consistent style to practice squash and stretch with expressions for animation practice, but in order to get there, I must practice my simple sketch consistency first.
I hope this is somewhat helpful to anyone having difficulty drawing the same face in different angles, or just faces in general, how cheeks and jaws work, etc. Or just have a laugh or two at my bad work =P