There is a full tutorial on YouTube showing how to make this cocktail, but here is the quick version:

2 oz. Good Vodka (Citron or Unflavored)

1 oz. Orange Liquor (Cointreau or Triple Sec)

1 oz. Simple Syrup

1 oz. Fresh Squeezed Lemon Juice

Optional: Sanding Sugar or Regular Sugar for the Rim

In a shaker cup filled with ice add the vodka, Cointreau, lemon juice and simple syrup. Shake well and strain into a martini glass with sugar on the rim.

Sanding sugar is not required, but it has more sparkle to it so it looks fancier.  You can find it on Amazon or in the baking section in the grocery store.