Shake or stir gin and dry vermouth with ice in a cocktail shaker. Strain into a chilled cocktail glass. Add olives on a pick.
Variations of the martini are endless. Vodka can be substituted for gin, add a dash of your favorite bitters, or to make a "dry" martini, decrease the amount of vermouth. Or try experimenting using sweet vermouth instead of dry. Traditionally, Plymouth gin is used but other types can be used, such as Old Tom or London Dry, can be used.
Also see the Vesper martini.