Sangria is best served chilled, so store it in the refrigerator in the serving container while the ingredients are soaking. Alternatively, you can serve it on the rocks by filling glasses with ice before pouring in the sangria.
Ideally, refrigerate sangria for at least two hours or overnight. And, by the way, sangria can last in the refrigerator for several days. Add a half-liter of soda water just before serving over ice.