Working with a non-erasable medium is a great way to practice your drawing. Pens and markers are excellent for developing confidence. One of the things I try and get across to my students who tend to draw light and timidly with a pencil, is to switch to something else that will put a permanent pigmented line down right away. It'll open up new areas and expand your abilities.
I did these doodles in preparation for class. All in ball point pen, with the exception of the 2nd sketch from the left which is a marker rendering. Click on the image and you'll get a better picture.
