Darjeeling tea: Use half teaspoon of leaf per cup. Brew for 3 to 5 minutes. Over brewing results in an unpleasant bitterness.
Assam tea: Use one teaspoon of leaf per cup. Brew 3 to 5 minutes depending on the desired strength.
Nilgiri tea: Use one teaspoon of leaf per cup. Brew 3 to 5 minutes depending on the desired strength. Oolongs because of their larger leaf size may be brewed a minute or so longer.
Darjeeling tea is best appreciated on its own. Though milk/sugar/lemon may be added, if desired, in small quantities.
Assam teas are lovely with a dash of milk that captures the malt flavour, tempers their strength and accents their richness, but they can be had with lemon as well. Modulate the infusion accordingly.
Nilgiri tea with its beautiful clarity, inherent tendency not to cloud and mild fragrance, makes an ideal iced tea both with or without flavour. It can be enjoyed as a hot tea as well, with lemon and honey or a drop of milk.
Squeezing lemon into tea might cloud the infusion. Use lemon wedges instead.