Step 1: Take a glass and add fresh mint leaves and a few lime slices. Gently crush them together to release the mint aroma and lime juice. Step 2 : Add sugar or simple syrup into the glass and mix it well with the mint and lime mixture. Step 3: Fill the glass with ice cubes and pour sparkling soda or cold water over the mixture. Step 4: Stir gently and garnish with extra mint leaves and a lime slice before serving.