Add tea, mint leaves, and citrus slices to a large teapot or measuring cup, and cover with boiling water.
Let tea steep for 10 minutes (less if using green tea).
Strain into a large pitcher, and add sugar or honey. Stir to dissolve.
Serve over ice, and garnish with mint and citrus slices.
Notes
If using loose tea, you may want to place the tea into a large tea ball or loosely tie it in some cheesecloth. After sweetening the tea, you can add the citrus slices right back into the pitcher - it's pretty and the slices continue to infuse into the tea as it cools. For an even more intense flavor boost, you can also add some fresh-squeezed citrus juice to the strained tea!