Read the commercial script. Break the action down into individual shots. The shots are what the camera sees or what the viewer will see on screen during the commercial.
Write a list of what the actual shots will be. Go through your sheets of paper, or blank storyboards, and number the order of shots.
Decide if the format is going to be in standard television 4:3 aspect ratio, or wide screen 16:9 aspect ratio. More of the visual frame will be exposed in 16:9, requiring slightly more dynamic visuals. This is usually the advertising agency's choice.
Sketch the action into the panels. Start lightly at first, using a harder lead pencil. Hard lead produces lighter lines. One you have the image the way that you want it inside the panels, apply more detail with a softer lead pencil. Softer lead produces darker lines.
Scan the black-and-white artwork into your computer. Open the files in Photoshop. Do touch-up work on the images as necessary until you are satisfied with the way they look.
Name your work and save it as a jpg file, or several files, inside one folder.