What ingredients do I need to make a margarita?

A margarita is an alcoholic beverage, usually made with a combination of tequila, fresh lime juice, and either agave or simple syrup. The ingredients are shaken with ice and then served in a glass over ice, often with salt on the rim. Optionally, you can add additional liquors like Cointreau to the margarita, or add additional fresh fruit juices for flavored margarita variations.