To make margarita mix at home, multiply the recipe for however many margaritas you plan to shake up. Then combine the orange liqueur, fresh-squeezed lime juice, and syrup or agave (if using) in a pitcher or container. Chill the mix for up to a couple of days. To make margaritas from the mix, shake the mix with the correct measure of tequila in a cocktail shaker, serve, and pour. To make two drinks at a time, measure out half of a cup of tequila. If you added simple syrup or agave, you will want to measure closer to six ounces of the mix for every two margaritas. Otherwise, measure five ounces of the mix, which equals half of a cup plus two tablespoons.