Elixir Fine Tea

Based on 1 teaspoon per 8oz cup (adjusted for leaf size - for larger leaf, increase to 2 teaspoon for example):

For white teas
Use 160F water (boil water, let stand for 3-5 min).
Steep 5 min for most teas.

For green teas
use 160F water.
Steep for 3 min.

For black/rooibos/herbal teas
Use 200F water (boiled water).
Steep 3 min for black teas.
Steep 4-5 min for rooibos and herbals.

There are many different guidelines out there with minor differences. Just remember that these are just guidelines. Use them as starting points and adjust to please your palate. You may wish to sample the tea at various time until you've got the right taste. Balancing the three brewing factors: amount of leaf; brewing time; and water temperature can be an art. However, experimenting can be part of the enjoyment. Whatever produces a cuppa you like, that's the best way to brew that particular tea.

Water
Tea can only be as good as the water with which it is brewed. Use spring or filtered water that has a natural mineral content. The fresher the water, the higher the oxygen content, and the better the taste of the final product. Distilled water is not recommended because it lacks the proper mineral and oxygen content; it produces a flat, bland infusion. Do not use hot tap water, water that contains chlorine or water that has boiled for a long time.

Brewing Utensils
In general, it is recommended that tea leaves need to be allowed to expand. In doing so, the leaves will more fully release the flavour and the nutrients. In his book, New Tea Lover's Treasury, James Norwod Pratt termed this "the agony" of the leaves.
Use a teapot or an infusion basket to allow the tea leaves to expand.