In your sketchbook, using graphite, draw (5 or more) contour line drawings of complex objects. One per page. Choose objects with many parts (i.e. athletic shoes, tools, bicycle parts, plants, car, toys, etc.) Focus on creating fluid, confident lines defining interior and exterior edges (volumes). Swelling or "accenting" the line will increase the volume (three-dimensionality). Note: There should be NO SHADING.
The two drawings above are excellent examples of this assignment. Notice the use of accenting in the paintbrush bristles as they extend out of the ferrule. Also, note the soft line work addressing the discolorations on the handle.
The composition for the hair clippers is especially well balanced and inventive to say the least. The placement and location of the cord and clippers is very effective. Notice how the cord divides the negative space into smaller bands allowing the clippers to hang in the largest negative area like fruit dangling from a tree branch.