The best way to steepa cup of black tea always starts by ensuring you clean your vessel very well, be it a teapot or a mug or a tea press. Then select good water (a bottle of spring water is recommended) and boil it in a clean kettle to 212 degrees Fahrenheit and pour it on your loose leaf black tea. The measurement is ~6 ounces of water to one teaspoon of tea leaves. Let it steep 30 seconds or to your preference. Keep in mind over-steeping will make your tea bitter.
1oz loose leaf tea = up to 15 servings of 6oz cups of tea (depending on how strong you prefer your tea)