Practice drawing lines at different angles - without rotating the page.
Create a sketch with a strong focal point.
Study proportion choices for the human body.
Draw without looking at the page, to capture the essence of the thing you are drawing.
Draw human anatomy, but use only convex lines for the outline.
On a model pose, observe the opposing straight and curved lines.
Do not think of anything, and start drawing as a meditation.
Draw poses, start with positioning the head, chest and hip.
Create rhythms in your work.
Create rhythm lines, then create a composition.
Design a consumer product.
Draw something with one single line.