Make a copy of or print an original eyeball image. Draw your own eyeball, copy one from a book or print one from the Internet. Re-size the image, if necessary. Resize online images with your preferred imaging program. Resize photocopied images by scaling up or down the output size.
Cover the image with a sheet of acetate. Temporarily tack the image and the acetate together with little pieces of tape at the top and bottom to keep them from shifting during the cutting process.
Cut out the pupil with a craft knife.
Cut halfway around the iris with a craft knife. Cut around the other side of the iris, but start and end the cut at least 1/8 of an inch from the ends of the first cut.
Position the blade of the craft knife at the start of the first cut. Make a cut through the sclera (the white part of the eye), stopping at the eyelid. Move the blade to the end of the second cut closest to where sclera cut was just made. Make a cut parallel to the sclera cut, ending at the eyelid and essentially making a strip through the sclera. The strip is necessary for keeping the pupil connected to the eyelid. Make a second strip extending from other gap between the cuts around the pupil.
Cut around the inner edge of the eyelid, stopping on either side each strip to keep from severing them. Allow the sections of the sclera, other than the strips, to fall away.
Cut out any additional, desired features, such as eyelashes or an eyebrow.
Untape the cut out acetate from the image.
Create a self-stick, removable stencil by spraying one side with repositional mounting adhesive.