Here's an example of a contour from my sketchbook. You don't have to draw only single objects but rendering a space or room is a good challenge as well, as in the R. Crumb example shown in class. My drawing started on the right with the corner of the countertop. I progressed to the left rendering the end table. I bounced back and forth a bit when rendering the couch and the baby activity box thing in the bottom left corner.
This next drawing has contour studies in ballpoint pen layered below the India ink pen. I tend to draw on the same page in layers. I almost did with the drawing above but resisted so I could show an example of "true" contour.The drawing of the utensils (below) is mostly contour with a few areas of solid, flat tone added for clarity and balance. Feel free to try something like this in your homework as well.
Faber Castell Pitt pens and ballpoint (with some marker from my 5 yr. old)