To draw a head looking up or down, you simply need to change the position of your guidelines for the eyes. For the normal view, the horizontal line for positioning the eyes is roughly in the center of the circle for the head. When looking down, the line is closer to the bottom of the head, and the facial features are closer to one another. The chin gets smaller and narrower while the forehead gets larger. When looking up, the line is closer to the top of the head, and once again, the facial features are closer to one another. The forehead gets smaller while the chin gets larger. Also, if your character has bangs, the point of origin of the bangs will move depending on the angle, as shown by the red-orange dot. There is no dot on the last picture because the dot is behind the head.
I will show other angles in a future tutorial.