Curved shapes are important in many paintings, not only in paintings with figures in them but also if you are trying to capture the gesture of a particular tree, an archway on a bridge, or a vase.
Many drawing books concentrate on teaching you to draw by following the outline of a curved shape as accurately as you can. This technique
is called contour drawing. However there is a major a major problem with this technique — it is very difficult to do accurately. Most people need many years of practice to become proficient at drawing accurate curves directly and getting them in the correct proportion at the same time. For many artists, including me, it is an impossible task. There is a much easier way to draw curves and get them accurate. It is called the straight line approximation technique.
In this technique, you approximate every curve by a series of straight line segments. It is much easier to get the proportions of these straight lines accurate. Once you have drawn these straight lines accurately, you can then easily convert them into curves as shown here. This is what you do:
Draw the straight lines.
Smooth the lines into curves.
You can use the straight line approximation technique to create beautiful drawings and paintings like this one by Pierre Paul Prudhon.
To learn more drawing techniques that will help to improve your paintings, see the Drawing Lessons.