To create a blind contour drawing (with a continuous line):
Fix your eyes on the outline of the model or object, then track the edge of the object with your eyes, while simultaneously drawing the contour very slowly, in a steady, continuous line without lifting the pencil or looking at the paper.
The end result doesn't matter - what is important is carefully observing the subject.
Here are two that were done today (by me) that students wanted to share: (There you go Connor and Kate! Enjoy! You have never looked so good! :))