As I said, practice makes perfect. You won't improve your pencil portrait drawing if you don't practice it. So, I have personally searched and picked 100 high resolution reference pictures to help you practice along with the home- study course.
I even edited all 100 of them to meet the criteria of going to "real master level" just for you. These 100 high-resolution reference pictures (divided into 70 faces and 30 facial features) allow you enough pictures to move from drawing individual facial features to drawing the entire face.
The best thing is, you don't have to spend hours and hours in front of your computer just to find a right reference picture for practice. I've already done all this for you.
Bonus to the "Realistic Pencil Portrait Mastery"