Good Quality water and proper brewing time are essential for a flavorful cup of tea. Start with a preheated pot or cup (simply fill your teapot or cup with very hot water and let it stand for a moment). Use fresh cold water. In areas with poor tap water, use bottled or filtered water. Never use water from the hot water tap. Let the tap water run for a few seconds until it is quite cold; this ensures that the water is aerated (full of oxygen) to release the full flavor of the tea leaves. Bring water to a rolling boil. Don't let is boil too long, as it will boil away the flavor, releasing oxygen, and will result in a flat tasting cup of tea. Pour boiling water over tea leaves or over tea bag. Brew 3 to 5 minutes. Leaving the tea leaves or tea bag in for any longer makes the tea bitter.
Ever wonder why your green tea doesn't taste like the kind you get in a Chinese restaurant? Chances are you are letting the water heat for too long. Heat the water just until you can hear it, and then take it off the heat. Water for green tea should never be boiled, it should just be hot. Steep green teas a maximum of 2 minutes to avoid bitterness.