Here are a few tips concerning the use of lemons in your Indian food: 1) Before squeezing a lemon for juice, put it in hot water, and you'll get more juice than normal. 2) A half a lemon placed in the refrigerator will help neutralize the smells of any stored food items.
The secret to making great chai is, of course, the spices (as it is with most Indian food). The fresher they are the better. Although what counts as perfect chai varies from person to person, it almost always includes whole cloves, cardamom and cinnamon, though nutmeg, ginger, and other spices are also common.