I took Nathan Fowkes' portrait workshop earlier this month after seeing posts on his website of the neat diagram he uses. It's a variation of Frank Reilly's diagram (Frank Reilly's teachings). I had it in mind while working on earlier variations of my model but this time I was paying a lot more attention to it. I found the workshop very helpful.
The cheek area continues to be the area I find the most confusing. In doing these I tried to keep in mind a comment from Nathan to keep the lines wrapping around the form and not going against it and a comment form Karl about paying attention to the way the forms are connected.