2oz Tequila, 3/4 oz Triple Sec, 3/4 Fresh Lime Juice, 1/4 oz Simple Syrup, Pinch of Salt
Shake all ingredients with ice, pour into a glass of choice strained over fresh ice cubes.  Marvel at the ease of a delicious drink.

To reiterate from the Mint Julep, a great cocktail has high-quality ingredients, precise proportions, and adapting to your own tastes.  In a margarita freshness is key. Generally, margarita mix has excess sugar, no triple sec, and preservatives.  The only way to guarantee quality is with fresh lime juice, 100% agave spirit, and triple sec with 35-40% alcohol (less sugar).  An fun way to adapt the margarita is to change the simple syrup.  You can use the mint simple syrup from last week’s mint julep, or try making a fresh fruit simple syrup.  Combine fresh fruit and with a half part sugar, by weight, in a zip-lock bag.  Let it macerate overnight in the fridge, the sugar will pull out the juices from the fruit.  Blend with 1 part water off the boil, fine mesh strain into a container, add a dash of clear spirit for preservative.   Finally, a staff favorite is adding Green Chartreuse or similar herbal, sweet liqueur.  Just a bar-spoon per drink adds a unique, herbal complexity.  Zipps carries both Green Chartreuse ($6.99/50mL) and the similar Boomsa Cloosterbitter ($3.99/100mL) in small sizes behind the counter.

Both un-aged and aged tequilas are perfect for making margaritas.  The aged tequilas can have a woody vanilla character from the barrel, while unaged, blanco tequilas have elements of fresh agave and sometimes a peppery spark.  Try either from quailty producers like:
Don Julio 
SALE $3 off $34.99/Blanco & $4 off $39.99 Reposado/ 750mL
Hornitos 
SALE $16.99 reg. $20.99/ 750mL
El Mayor
SALE $7 off $23.99 Blanco, & $26.99 Reposado/ 750mL
Exotico
SALE $14.99, Reg. $19.99/ 1L

If you cannot decide, there is always Libelula Tequila Joven ($23.99/ 750mL), a blend of both unaged and aged tequila constructed for making an excellent margarita.  Finally, mezcal makes for great margaritas.  Del Maguey Vida ($32.99/ 750mL), Cruz de Fuego ($36.99/750mL), and Banhez Espadin ($27.99/ 750mL) are all great bangs for the buck.