Chill the martini glasses for a few minutes. Also, chill the Cocktail Shaker for a couple of minutes.
Add ice to your Cocktail Shaker.
Pour the cranberry juice, orange flavored liquor, vodka, and a generous squirt or two of the fresh lime juice (Key Lime juice would be preferable if you can find it) into the shaker.
Put the cap on the shaker and shake.
Strain the liquid into the prepared martini glasses.
You will also need a good Cocktail Shaker.