I always make sure every single ingredient is cold before I start mixing. Warm juice mixed with soda loses its fizz almost instantly, which flattens the whole punch. Popping the cans and bottles in the fridge a few hours ahead saves you from watering everything down with extra ice later.
In a large pitcher, I stir together the cranberry juice, orange juice, and the thawed cranberry juice concentrate. I give it a good whisk so the concentrate fully dissolves instead of sitting in clumps at the bottom. This juice blend is the flavor backbone, so I always taste it here before adding the fizzy part.
Once the juice mixture is well combined, I pour it straight into my punch bowl over the ice ring. I like resting the ice ring gently against the side so it doesn't splash juice everywhere. This step is where the punch starts looking genuinely festive.
Right before serving, I slowly pour in the chilled lemon-lime soda or ginger ale. Pouring it down the side of the bowl, rather than straight down the middle, keeps it from fizzing over. I stir just once or twice, gently, so I don't knock out all the bubbles.
Finally, I float the fresh cranberries and orange slices right on top for that holiday-worthy look. A few sprigs of rosemary tucked in make it look even more special for a dinner party. I serve it immediately while it's still bubbly and ice-cold.