According to my family, these are the important lessons in green tea preparation:

• Use about 1 tablespoon of green tea
• Never use boiling water or even water directly from a hot pot. My family often uses two tea pots: one to let the hot water cool down in and one for the tea.
• When pouring tea for multiple people, never pour an entire cup at once. Keep pouring a little into each cup until they are full. Everyone will get better tea that way.
• Good tea should be reusable multiple times. Some of the tea I got in Japan is rated for seven uses.
• The tea should be a pleasant green color, not yellow. Yellow may mean that the tea has steeped too long or the tea is used up.
• After the inital batch, you shouldn't have to wait for subsequent batches to steep. Pour a little into a tea cup and see how it looks. If looks too light, let it steep a little longer.
• Tea has an expiration date but you can get past that by putting your tea in the refrigerator.