Technique
Press the mint gently with the sugar and lime juice just until the leaves smell strongly of mint. Add cracked ice and rum, then lift the ingredients from the bottom with a bar spoon before topping with the remaining soda water.
A mojito is a traditional Cuban highball. The cocktail often consists of five ingredients: white rum, sugar, lime juice, soda water, and mint.

TonicDB editorial guide
A Mojito works because mint aroma, fresh lime, sugar, rum, and carbonation arrive in layers. The goal is a bright highball with fragrant mint—not a glass full of pulverized leaves—and the final soda should keep the drink lively rather than dilute it into flavored water.
Press the mint gently with the sugar and lime juice just until the leaves smell strongly of mint. Add cracked ice and rum, then lift the ingredients from the bottom with a bar spoon before topping with the remaining soda water.
Serve in a tall glass packed with ice and leave enough room for the soda. Clap the garnish sprig once between your palms before placing it near the rim; releasing its surface oils makes the first sip smell fresher without adding more leaves to the drink.
Aggressive muddling tears mint into bitter fragments that clog the top of the glass. Another common mistake is stirring after all the soda has been added, which knocks out carbonation; mix the dense ingredients first and give the finished drink only one gentle lift.
Simple syrup can replace the granulated sugar when you want faster, more consistent mixing. Start with about half an ounce, taste, and adjust for the tartness of the lime rather than assuming every piece of citrus needs the same sweetness.
These notes explain how to execute and adapt the recipe shown above. Ingredients and serving traditions vary, so taste and adjust thoughtfully.
Contributed by @alfg