Mandy Monkcom, a local artist, guided us through creating figure sketches from images.
Create quick sketches to get used to shape and form. Use a granite pencil on white paper to get an idea os shape and form. Do not worry about detail as you're not aiming for a finished piece.
Use the head size to help assess the size of the figure from the head to feet - usually about 7.5 heads. Plan out the shape with the oblong head and feet lines keeping the whole form on the paper.
Add construction angles - lines for hips, shoulders and waist and include where hands finish and a central vertical line through the head which really helps with proportion. (Just a note that elbows usually are in line with the waist.) Finally add movement or action lines which are often curved. All these lines will give a framework to work with in sketching your figure.
Emphasise negative spaces such as gaps between waist and elbow. Hands and feet are tricky, so just create an outline. Use clothing lines on the body to give an idea of shape. A useful tool is to draw the body outline on clear film and review the shapes created on the film to make adjustments on paper.
Once you feel comoftable in pencil, progress to creating sketches in black and white charcoal, using similar principles as graphite pencil. (Charcoal can be rubbed out.) Use white charcoal sparingly and try to avoid blending white and black charcoal as this becomes grey and the sketch becones blurred.