Instructions
Sit down at your desk and write a short sentence with a pen. Take notice of the muscles you use when writing -- are you using mostly your fingers or your whole arm? If you only use your fingers, you will have a longer path to clean writing.
Hold your pen between your first and second fingers and secure it with your thumb. The pen should lie just below the third knuckle on your middle finger.
Grip the pen with a light touch. A death grip on the pen contributes to cramped, shaky writing.
Write using your forearm and shoulder muscles. Smooth, legible writing starts at the shoulder and proceeds down the arm, with the fingers serving to keep the pen in place. Practice this by making huge letters in the air, then reducing their size, until you can practice on paper.
Create a word processor document and use your favorite smooth font to type the alphabet. Print this page out and try to mimic the letters in your writing.
Practice writing for at least 30 minutes each day. Focus on uniformity and smoothness and remember to use your entire arm. The more your practice, the more natural the actions will feel.