Step 1: Take a picture or borrow one accidentally on purpose, convert it to greyscale and lighten it by 60%.
Step 2: Print it out and trace over it quickly with a black felt tip pen and scan it in.
Step 3: Open both the scan and the original image in photoshop. Copy and paste on over the other, line up and multiply the top layer. Yeah, grittier and grundgier the better!Step 4: Learn how to use Illustrator.