Combine all ingredients in a shaker tin and shake vigorously. (NOTE: "Gold" or "Resposado" Tequila is preferred over silver for a bolder, stronger flavor, but use "Silver" or "Plata" for those that want a lighter tequila flavor. Also, add more lime juice for a tarter flavor or more agave nectar for a sweeter flavor.)
Strain into martini glass.
Salt rim of martini glass as preferred.