Use fresh leaves. Select good looking, healthy citrus leaves. Wash the leaves. Boil a pot of water. (I use a glass pot, not a metal one.) Drop the leaves into the boiling water, cover the pan, lower the heat and allow to simmer for 10 minutes. Turn off heat. Cool completely. Strain out the leaves (you can add the leaves to the compost bin). Refrigerate the tea. The color of the tea will look a bit greenish-yellow. You may want to sweeten with honey or sugar. I like to add a sprig of fresh mint or lemon balm to the glass when serving - looks nice and tastes good.
Plus, it's okay to dry the leaves to use later so you can make the citrus leaf tea in the winter.