For a perfect tea use about 2 g of tea per cup (1 teaspoon of tea leaves for a 1,5-2 dl of tea). Tea leaves can be used more than once.
Boil the water and then let it cool for a while. Boiled water usually requires 30-60 seconds to cool to approximately 80° C which is the appropriate temperature for Green Teas. Only then you can pour it on the tea leaves and avoid the bitter taste.
Green Tea leaves should soak for 1-2 minutes.
In case you want to reduce the caffeine content, pour the hot water on the tea leaves just enough to cover them. Then let the tea stand for about 20 seconds and take away the water. Finally you can follow the standard procedure of preparing the Green Tea.