Eddie Pensier writes:

1. Green and white tea should be brewed at lower water temperatures (75-80* degrees Celsius) than black or herbal tea (boiling 100 degree water). Too-hot water can burn the more delicate leaves and cause a bitter, over-extracted brew. If you haven’t got a temperature-controlling teakettle, here’s a trick: fill your teakettle 3/4ths full with water, boil it, then fill it to the top with cold water. The water will be at the perfect temperature for green and white tea. You might even discover you like it now, if you’ve been preparing it incorrectly all along.
2. Want some tea but don’t want the caffeine, and don’t have any decaf tea on hand? Brew your tea, strain, and save the brewed tea for another time, or just pour it down the drain. (Or let it cool and use it to water your houseplants.) Use the same leaves to brew another cup. The second cup will have very little if any caffeine. Good quality loose-leaf tea can be re-steeped up to four times, sometimes more. Tea bags can be reused twice but are best disposed of after one use.
3. If you want a stronger flavor to your tea, use more tea leaves per cup rather than steeping longer, which can cause bitterness. The standard measurement is one teaspoon of dry tea per cup (250mls) of water. Use a little more if you prefer.
4. Many tea guides will swear that you need filtered or spring water to make good-tasting tea. I have never found this to make enough of a difference to be worth the expense. If your tap water is safe to drink, and tastes good on its own, it will make fine tea.
5. One of the questions I’m asked most often is, How do you make iced tea? The obvious answer, “make a pot of tea and stick it in the fridge”, never seems to occur to people. (When I arrived in Australia over a decade ago, iced tea was still considered a grotesque Yankee abomination by many, especially older folks. It’s starting to catch on.) But you can also try the “concentrate” method: Pour a liter of warm water over 50 grams of your favorite tea. Put the mega-tea in your fridge overnight. (Yes, this appears to contradict #3 above. The warm water rather than hot water mitigates the long steep and prevents over-extraction.) In the morning, strain, and you’ll have just under a liter of tea concentrate. Mix in a 1:3 ratio with cold water and sweeten to your taste for perfect iced tea.

*A Celsius-Fahrenheit converter for those of you who may need it.