Concerning my love of the ballpoint pen for sketching...that was one of the first things I was taught in art school. I am a graduate of AAA (The American Academy of Art) in Chicago and before I went there I never really did any art other thatn drawings with a pencil. Not even an artsy fartsy one. Just the good old #2 yellowy one with the eraser on top. (Why do those always dry out?) My beloved hardnosed life drawing teacher Arvidas Algiminas (a fine FIne Artist with the oil paints) kicked all our freshman behinds by making us spend the first 45 minutes or so of our 3 hr life drawing class doing super quick sketches in ballpoint pen.
The model would strike a pose and every 3 minutes or so (sometimes more, sometimes less) Al would say "Change" and the model would strike a new pose.
You had to be fast and you could not be concerned with the details.
This is how you BUILD confidence.
You need not have it before you sit down.
If you are too concerned with the likeness or something you are only building your reticence. If you don't want to use a ballpoint, get one of those great big leds that are as thick as a charcoal piece. I got one of those when we were at a convention in Italy and I haven't had much chance to use it since. But I made some great gesture drawings with it...
Also, hold your pen or pencil loosely for this. Someone should be able to walk up to you as you are drawing and pluck it easily from your fingers. Clutching it in a death grip will give you "th' tendonitis! "
I'll dig around in the basement and see if I can find any of my old art school stuff. I know I have something.