A teapot with a built-in strainer will prevent leaves from entering the spout. To allow flavor to develop fully, brew tea loose, not in a tea ball or infuser. Different teas have different weights. With lighter weight teas, be sure to add enough leaf. Use about four grams of tea per eight ounces of water.
Tap water contains chemicals that affect the taste of the tea.
Try different spring waters, or filtered tap water. Don't re-boil water as much of the oxygen will disappear, resulting in a flat brew. Do not use boiling water when brewing white or green tea. Over-heated water will cook the leaves and destroy their flavor. Pay attention to taste rather than color.