As an exercise you can learn a lot from masters like Holbein that added an amazing sense of perspective to their portraits. Find some of their masterpieces and try to trace them applying the loomis or reilly method of construction, simplifying the features. I know it won't be as dynamic, but later you can deal with other views of the human head. Steve Huston has a course on constructing the human head, and Ramon Hurtado has a great gumroad on it as well https://gumroad.com/ramonhurtado?sort=newest#TPlxp. You can give a look at Stephen Bauman's channel, he is always doing livestreams so you can see how he does it https://www.youtube.com/channel/UCqEWLv392F0J9rN7jE1-f3w .Keep in mind, you are building a head, not outlining an image. Good luck!