Cut out a rectangle out of your fabric. If you are using a cushion to stuff it then make sure to cut a large enough rectangle to cover it.
Take your fabric, width ways, and fold under 1cm of fabric and pin a zip underneath.
Sew the zip in to place using a sewing machine. Make sure not to sew on to the metal zipper or you will break your needle.
Fold over a cm on the other side of the rectangle and pin on to the zip.
Unzip the zipper and sew in to place.
Fold the fabric inside out, so that the wrong side of the zip is facing out. Half zip the zipper shut. Pin the open sides of the square together.
Sew up the first side.
Sew up the second side. Make sure the zipper is halfway unzipped before you start or getting in to it will be a nightmare.
Unzip the zipper fully and fold inside out. You have now made your cushion cover.
To decorate it, pick a page from your favourite comic book. Scan it in and then print it out on reverse. If you have a lazer printer this will work fine otherwise you will need to get a photocopy. Use the method described in the <a href="http://www.cutoutandkeep.net/projects/fabric_printing">fabric printing tutorial</a> to print the comic on to the cushion.
When the ink has dried use a black fabric pen to re-touch any areas that need to be.
Take a grey fabric pen and add mid-tones to the comic. Then fill the cushion cover, either with an old cushion or stuffing.