Sprinkle some sea salt on a small plate and set aside. Rub the rims of 4 glasses with a lime wedge (you can also use an orange). Press the rim of each glass in the salt, turning it around so the rim is coated. Set glasses aside.
Stir together the lime juice, orange juice, tequila and agave nectar in a pitcher. Taste and add more juice or nectar, if desired.
Fill glasses full with ice then divide the margarita mix into the glasses and add a slice of lime. Serve!
Notes
Make these spicy by adding cinnamon (or cinnamon liqueur) to the mix!
For margarita slushies, you can add all ingredients and ice to a blender and make frozen margaritas.