Step 1.
- Rim the highball glass with salt by wetting the rim with a slice of grapefruit and dipping it in salt.
Step 2.
- Fill the glass with ice.
Step 3.
- In a shaker, combine the tequila, grapefruit juice, and lime juice.
Step 4.
- Shake gently and strain the mixture into the prepared glass over the ice.
Step 5.
- Top up with club soda.
Step 6.
- Garnish with a slice of grapefruit.