Add ice to a cocktail shaker followed by the tequila, agave nectar, and lime juice.
Shake vigorously.
Strain into a chilled coupe glass or martini glass.
Garnish with a lime wheel.
Notes
Fresh lime juice is best but you can also use store-bought 100% lime juice. Rose's Lime Juice (also known as Rose's lime cordial) can be substituted, but since it is sweetened, decrease the amount of agave nectar called for by ¼ of an ounce.
Gimlets are traditionally served straight up in a coupe glass, but a martini glass can be used as well.