Creating a wireframe on paper is an intimidating task for people who can’t draw well. “How to Draw a Wireframe (Even if You Can’t Draw)” by Kelley Gordon breaks down the process of creating wireframes on paper for those of us that aren’t artistically gifted.
Gordon shows that most elements that appear in a wireframe can be represented using basic shapes, like lines and circles. Low-fidelity wireframes don’t have to be perfect and are done to “explore possible solutions to design problems.”
If you’re prone to perfectionism, use thick pens or sharpies, allocate a limited amount of time to complete the wireframe, and limit the space (on paper) you can use for your wireframes.
You can purchase handy UI stencils from several popular online retailers if all else fails.