Getting Started: The Rough Cut
Take one fulled/felted/shrunken sweater, and, using pinking shears, cut along the seams to separate the pieces (front, back, sleeves). You should be able to make two aprons out of one sweater. Hold the body piece of sweater up to the recipient for sizing. Make adjustments to length, width, neck shaping, etc. This sweater was just right for my son, so I didn't alter the shape. The second apron I made (see end of this flickr set) was a slightly different design with more altering. Use your imagination and let the sweater give you ideas for what works best.