h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

What is the proper technique for brewing green tea at home? Are there any particular guidelines which should be followed to ensure the best-tasting green tea?

First of all you got to make up your mind on how many leaves to use.
I suggest one to three teaspoons per litre of water. Your mileage may
vary, so you should experiment around a little. In my experience taking
not enough leaves is not as bad as taking too many. The latter makes
your tea bitter and not a pleasure to drink.

The next thing is water. It should be at 60 - 75 degrees Celsius. I
usually go for 70° C. There is some debate on whether the water should
be brought to the boiling point and then cool down or if you just heat
it up to 70°C. I use the latter and see no reason to complain. =)

You then pour the water over the leaves and let the tea infuse for about
two minutes. Then separate the leaves from the water by removing the
tea sock or whatever you are using. I have a Bodum(r)-teapot, so I
just press the plunger.

Pour yourself a cup and enjoy. I found out that letting the tea cool
down in the cup can improve the taste.
Adding sugar or milk is a sin. You gonna burn in hell for doing so. =)
(No, actually, if you happen to like that, it's okay, but you should
at least try it "pure" once.) Surprisingly, I found that adding a
little lemon juice can be quite tasty, though I prefer my tea pure. =)

The main point is to take good care of brewing the tea. Taking the right amount of leaves is *very* important, and if you find your
tea to be bitter, try less leaves the next time, and you might be
surprised - just one teaspoon can make the difference between a
subtle delicate miracle and something that tastes like you brewed
grass from your garden.
If that doesn't help, try cooler water, let it infuse for a shorter
time. Also, green tea leaves can be infused more than one time, and
the more often you do so, the more comes out of the ... well, more
subtle flavor. And some good teas can be infused for 4 to 5 times,
maybe even more often.
Good green tea looks approximately like urine is supposed to look,
pale yellow (to green - well, urine's not supposed to be green...) and
transparent. The darker and the less transparent it gets, the worse
is the taste, usually. If it is properly done, the tea should not
taste bitter. Keep that in mind.
And, of course, enjoy!