Start by making the ASL sign for the letter 'P', by making your dominant hand into a fist and extending your index finger upward and your middle finger at 90 degrees. Then touch the 'P' letter to first your non-dominant shoulder, then your dominant shoulder, then your dominant hip.
Princess and the other royal signs make a great companion to fairy tales such as Cinderella and Snow White, which feature these characters.
Print out all four of the royal signs: king, queen, prince, and princess. Then teach the signs for the four words together so your baby can learn the meaning of the words by observing the age and gender contrasts between the four cards.