From
The Sketchbook Challenge is... ::drumroll::
OPPOSITES
This is wide open. You will make your choices as you go along. Consider this: the best way to enhance something in an image is with its contrast, its opposite. A warm color will be set off with just the right touch of a very cool color. Rough texture is emphasized by smooth surface. Agitated lines have a stronger voice when contrasted with gentle areas.
Opposites include those of color, temperature, orientation in space, kinds of marks... and more.