Fill a cocktail shaker halfway with ice and add the gin or vodka, and vermouth. Shake vigorously for 10-15 seconds to chill the ingredients. Strain into a martini glass.
To prepare the dry martini:
Place 1-2 green olives in a martini glass.
Fill a cocktail shaker halfway with ice and add the gin or vodka, olive juice, and vermouth. Shake vigorously for 10-15 seconds to chill the ingredients. Strain into the prepared martini glass.