I like to leave about 1/2 cup of the cranberries aside for garnish.
You can also slice the zest from the oranges and set aside for garnish before slicing them and adding them to the drink.
You can use all cranberry juice or a combination of cranberry and whatever else you like. We love this Christmas punch with cran-raspberry or cran-apple juice as well. If you'd like to use frozen juice, just mix the frozen juice as directed on the package and use that in place of the bottled juice.