Lets begin with the circle exercise Yes, circles.
Draw a series of circles as uniform as possible going up and down the page. Don't spend time aiming to make them perfectly round. Instead, draw them at a steady pace.
The purpose of this exercise is to loosen up your hand, to help you get a comfortable grip on your drawing tool (pencil, pen, etc) and to help you get some of that initial drawing rustiness out of your system.
This is a great step to take before you begin drawing anytime. It is also great to do while you're on the phone, watching TV or during any down time.
I know it seems amateur, but it is great practice.