Cut rectangles out of foam sheets that measure 3 inches wide by 6 inches long. Consider using pink foam sheets for girls or blue for boys, although any color will do.
Place a circle cutter in the top center of each foam sheet and cut out a circle. Cut a slit in the right side that reaches into the circle. This is how you will slip the size tag on the rod in your closet.
Stick letters and numbers above the circle to identify the size. The easiest way to do this is with letter and number stickers. You may have one size tag that reads "6 to 12 months" and another that says "2T." It just depends on what size clothing you have in your closet.
Print some clothing images or clip art to use to decorate the front of the size tags. Your computer may already come with some images, but you can also get free clip art images online. Use pictures of pants, sweaters, dresses or overalls.
Glue the image to the front of the size tag, just underneath the circle. Wait for the glue to dry before using in your closet.