Bring the water to a boil, then let it cool to about 80°C (175°F) — this way the tea won't turn bitter.
Steep the green tea for 2 to 3 minutes, then remove the bags or strain.
Let it cool completely, then add the citrus juices and sweetener.
Stir everything together thoroughly.
Serving: Pour into glasses over ice, then garnish with citrus slices and mint leaves.
For an even more refreshing result, add a splash of sparkling water — that way you get a light, bubbly version of the drink.