This is a 3-page sketchbook exercise.Use graphite. Get a friend to model for you. Have them hold a post facing you directly for 10 minutes – fill the page with this pose. Have them turn 45 degrees, and draw the same pose for 10 minutes on a new page. Finally, have them turn another 45 degrees (now you should see them facing 90 degrees or sideways from you), and draw the same pose.
“A good artist simplifies, deconstructs, reinterprets, and understands his subject matter. Many of the world’s greatest portrait painters openly admit that the better their personal connection with the person they’re drawing, the better the finished portrait will be – because they know their subject from a variety of angles.
Our eyes only see raw jumbled light. Our brain takes this light and sorts it out into objects with form and texture. Drawing things from multiple angles makes our brains better interpreters of light. Children draw what they think something looks like; amateur artists copy what they see; master artists draw what they understand.
Draw a person from multiple angles. Imagine you need to make a record of how they look but you have no camera at hand. Even though you’re using different viewpoints, there should be a basic likeness between them all.”
Exercise borrowed from here.