Fresh grapefruit juice and tequila with a splash of mineral water and a drop or two of agave makes a not-too-sweet great alternative to the standard margarita.
Fill a small plate with kosher salt. Wipe the rim of a glass with a wedge of lime. Dip the moistened rim into the salt. Fill the glass with ice. Add grapefruit, tequila, soda and agave. Garnish with a wedge of citrus.