Black tea is a wonderful tea for beginners and experts of loose leaf tea. It is easy to steep, but offers lots of variations and complexity!
As a general rule - 2tbls of tea for a standard size cup, 3tbls for a large cup. You can adjust to your taste preferences. If you like a strong cup of tea, I recommend adding more steep instead of steeping longer! As steeping longer brings out more bitter tannins.
When steeping tea, especially a good quality looseleaf tea - use a lower than boiling temperature water. I usually use 195F for black teas. Don't worry about being too exact, but letting your water cool for a minute before steeping will give you a better cup
Steep time - Try steeping the tea for a minute and a half (1min 30 sec), then take a small sip. If it is not flavorful enough let it steep for 15 second intervals.