1. Find a public place where you can observe other people unobtrusively. The best places are places that are somewhat crowded, and where people typically sit down for awhile, such as a park, courthouse or coffee shop. Airports are great for this, and so are restaurants.
2. Open your sketchbook so you have two blank facing pages.
3. On on side try to draw the heads of the people around you. Notice the things that make people's heads and faces distinctive, like head shape, hair, and distinctive noses, mouths or expressions. See if you can capture the things that make that person's appearance distinctive.
4. On the other side draw hands. Notice what people use their hands for; are they grasping or holding something, or are they pointing or trying to convey emotion? Try to capture the essence of what the hand is doing or communicating.
Why this is important
We do most of our nonverbal communicating with our facial expressions and hands. Faces and hands are also among the hardest things to draw. One of the reasons is that our perceptions are finely tuned to faces and hands -- we pay a lot of attention to faces and hands on a daily basis -- so when we look at a drawing the smallest error seems to stand out.
Don't be discouraged if your first attempts fall flat. Keep trying. If you can learn to draw convincing faces and hands, everything else will seem simple by comparison.
You can read more on sketching and visual thinking in visual thinking school.
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