Place salt on a plate. Rub a lime wedge around the edge of a margarita glass. Roll the rim of the glass in the salt to coat the rim.
To a cocktail shaker filled with ice, add the tequila, Grand Marnier, lime juice and agave nectar. Shake well.
Add ice to the prepared margarita glass. Strain the cocktail over the top. Garnish with a lime wedge.
Notes
Use the best ingredients you can afford. Make them as top-shelf as you can.Roll the outer rim of the glass in salt, rather than dipping the top in straight down. This keeps salt from getting in your beautiful margarita. When juicing, use room-temperature citrus to get the most juice out of your limes.