Here's how to make a COSMOPOLITAN !

1 ounce Vodka (depending upon how strong you like your drink- our measure is a shot glass of one ounce)
1 ounce cranberry juice
1/2 ounce Triple Sec (or Grand Marnier) juice from 1/4 or 1/2 a lime (depending how you want to use the lime juice to balance the sweetness of the other ingredients)

Put everything in a cocktail shaker, add crushed ice to almost fill shaker

Shake for about 10 seconds, then pour into a martini glass.