Shave the beret using a regular shaver; either wet or dry.
Get the beret soaking wet and ring out the excess water.
Place the beret making sure the band is horizontal around your entire head. Begin combing over the excess beret from the left to the right while holding the stiffner with your left hand.
Pull all the excess beret over to the right side, then pull some of the excess fabric over the flash and the front side of the beret, still holding the stiffner with your left hand.
Keep holding the stiffner until the beret begins to dry. Keep it on your head for a long period of time.
Once the beret is formed on your head, take the beret off, put a paper clip behind to hold the excess over the flash (optional but recommended), and place it on a flat surface with the excess part hanging off the edge.
Wait a day for it to dry. This is the final step of forming a beret.