just measure the width your machine, x the depth (gonna be approx 20 x 8) now add a 'drop' length that does not interfere with your legs...(approx 6--8 inches). (so now we're up to 20 x 16)... i would take 2/3 of the drop length and lay a piece that high on top for a pocket... now repeat with a piece that is 1/3 that high.... so far, with a 6 inch drop, you would have a 4 inch pocket and a 2 inch pocket on top of that... each pocket should be sewn into different size divisions... maybe on 2 pocket in the front ...since it's shallow, you could lay pencils in one and a little 6 inch ruler in the other... then 3 divisions in the 4 inch pocket... big enough for post its, extra feet, etc. with all the layers together, add batting (for sound dampening) and backing and bind all together. then glue a bit of rubbermaid drawer/shelf lining to the bottom for non skid.... the drop, the size of the pockets and the number of pockets are all adaptable to your own personal needs....