Chill your glass. If possible, pop a highball or balloon glass into the freezer 10 minutes before making your drink.
Add ice. Fill the glass with large cubes or a spear to minimize dilution.
Pour the gin. Add 2 oz of Tanqueray Rangpur Lime Gin over the ice.
Top with tonic. Slowly pour 4–5 oz Fever-Tree Elderflower Tonic to preserve carbonation.
Garnish. Squeeze a lime wedge over the drink and drop it in. Add mint or an edible flower if you’re feeling fancy.
Stir gently. Just once or twice to integrate the ingredients without losing fizz.