Giacometti was a master of cross contour, and he invented a way of building up line, then painting over it and continuing to draw on it.
Alice Neel was highly selective in her focus. She made powerful choices in her work, rendering some things with intricate detail and others elements as blocky patterns and heavy outlines, with no detail at all.
Richard Diebenkorn was a master American expressionist, who was able fuse abstract qualities with representation. He worked in a pure abstract mode as well as studying representation and in the course of his work found a way to bring these two ideas together.
Do a still life drawing for 30-40 minutes in the style of Alice Neel. Carefully compose your work. Start with the major proportional elements in your view. Use a piece of colored pastel so that you have a light under-drawing. Finish with black compressed charcoal. Choose one element of your drawing as the focus, and treat the other elements in your drawing as pattern.
Talk about your drawing and tell us how you approached it and how you understood the idea. These are psychological and emotional concepts so there is no right or wrong and your ideas are more important than the reference artists.
Change position in the class and do another drawing. Focus only on composition and proportion and see if you can come to an emotional connection with your drawing.