Fill a highball glass with ice to chill it and let it sit while you gather your ingredients. Once your glass is chilled, discard the ice and fill with fresh ice cubes to the brim.
Pour 2 ounces of gin over the ice. And add 1/2 ounce of freshly squeezed lime juice.
Slowly top the glass with chilled club soda, leaving about an inch from the top and stir gently with a cocktail spoon to mix. Garnish with a lime wheel or wedge, if desired.