Add all of the ingredients except the garnishes to a cocktail shaker, then add ice. Shake vigorously for 45-60 seconds.
Fill up two glasses to the brim with ice. Pour over the margarita mixture evenly into both glasses
Garnish the glasses with frozen cranberries and lime wedges, if you'd like.
Enjoy!
Notes
To make simple syrup, combine even parts water and sugar to a saucepan, and simmer on low heat until all of the sugar is melted. For example, you can use 1/4 cup each water and sugar.
I like Ocean Spray's Diet Cranberry Juice because it has zero added sugar!
I highly recommend using a cocktail jigger to measure the ingredients. However, if you don’t have one, here are the liquid conversions: