Experience is the best teacher, and each tea drinker will find the best brewing for each tea with practice. Keep in mind both the basic concepts of brewing and the specific pointers for the type of tea.

Start with fresh, filtered, cold water
A cup of tea is about 98% water, so using good quality water is imperative for making a great cup of tea. Bottled or filtered water is recommended when old plumbing imparts an unpleasant flavor, or in areas with noticeably chlorinated or hard water. Water with 50 - 150 ppm total dissolved solids or 1 to 3 grains hardness seems to provide the best results.
The freshness of the water is important as well for its dissolved oxygen content, which seems to enhance the quality of the extraction. For this reason, never use water from the hot tap or water that has already boiled for a long time.

Preheat the pot
It is important to preheat the pot or cup in which the tea will be steeped. If poured into a cold porcelain vessel, boiling water will immediately drop several degrees, diminishing the extraction. To preheat the pot: as the water is heating in the kettle, pour a little into the pot to warm it; then pour this water off into the drinking cups to warm them.

Measure carefully
We recommend using 3 grams of dry tea leaves for each six ounces of water, or one-half ounce of tea leaves per quart of water. Since most people don't readily have a gram scale for weighing, measuring one rounded dinner teaspoon per cup will do (a measuring teaspoon tends to be too small). However, it is important to compensate for the varying leaf size of individual teas. F.O.P. grade teas will require slightly more volume of leaf than B.O.P. grade teas. Some oolong teas have such large, wiry leaves that twice as much volume of leaf is required to compensate for the lack of density of the tea. And for Gunpowder green tea, the leaves are so densely packed that 2/3rds of a teaspoon will do to make a cup. No matter what the tea, adjust the volume of leaf to achieve a strength of 3 grams tea per six ounces water; this will yield approximately 150 cups per pound of tea.

Brewing Black Tea
"Bring the pot to the kettle, not the kettle to the pot" goes the old saying, and this is for minimizing the heat loss from the moment the heat is removed to the moment of pouring. Black teas require water at a full rolling boil, and the lid should be clapped on immediately afterward. Don't boil the water too long, or the oxygen content of the water will be reduced and lend a flat taste to the cup.

Brewing Green Tea
Unlike other kinds of tea, green teas do not take well to boiling water, but do best with water in the range of 175°-190°F. Japanese green teas tend to take water best 175°-180°F; China green teas tend to taste best at 185°-190°F. To brew green tea without a thermometer, pour the water just at the moment that bubbles begin to rise from the bottom of your kettle, or bring it to a boil first and then let it cool for two to three minutes before pouring. It's important to have a dedicated teapot for green teas, so as not to cloud the flavor with residue from steeping black tea.

Brewing Oolong Tea
Most oolong teas require brewing water to be at a full rolling boil, just like black teas. Greener oolong teas such as Ti Kwan Yin are light enough in oxidation that they can take water at 195°F, but boiling water will deliver more flavor.

Brewing Herbals (Tisanes)
Herbs should be brewed just like black teas, with water at a full rolling boil. Again, to avoid any cross-contamination between the flavors of tea and strong herbs such as peppermint, it's best to have a dedicated teapot for each.

Time the Steeping
To get the most flavor out of any tea, the best standard is a five minute steep time, which is what we do in the cupping room at Peet's. However, it should be recognized that some of the teas of India and Sri Lanka can be quite powerful tasting, especially the broken grades which tend to infuse more quickly due to their smaller leaf size - so four or even three minutes can be quite appropriate for these teas. Green teas tend to like a four minute steep. Herbal tisanes (which are not tea) tend to be much less sensitive to steep time than true teas are, and tend to produce a good cup anywhere in the range of three to seven minutes, depending on the herb.