1. Collect plastic bags and make balls like in the photo. Pom poms can, of course, be made from just one color, but they're even more stunning when made from a mix of colors.
2. Decide how large you'd like to make your pom poms, and then cut a piece of cardboard whose width measures roughly the size of the desired pom pom. You can always make the pom poms smaller if they end up being bigger than needed. For the small medium and large pom poms cut pieces of cardboard that are 6", 4" and 2" respectively, and finished pom poms measured 7", 4.5" and 3" after their haircuts.
3. Wrap plastic ball around your piece of cardboard around 20 times, combining the colors of your choice.
4. Remove the ball from the piece of cardboard, and tightly tie a piece of string around the exact middle of the ball, as seen in the image.
5. Cut through the loops of plarn using scissors, if it becomes difficult, just cut off the ends in order to open the loops. Fluff up the pom pom and then trim it to make it as round as possible.