1. Fill the glass with ice and swirl to chill the glass.
  2. Discard the remaining water.
  3. To boost the flavor of the cocktail, add a few lightly crushed juniper berries so they release their unmistakable aroma.
  4. Pour in the gin and top up the glass with tonic while stirring gently with a spoon.
  5. Adorn the rim of the glass with a wedge of lemon or lime to give the cocktail an added citrus twist.