King and Queen - wears gold crown with points all around. Address as "Your Majesty."
Prince and Princess- wears silver crowns with one point in the front. Address as "Your Highness."
Duke or Duchess - wears gold coronet decorated with strawberry leaves. Address as "Your Grace."
Count or Countess - wears gold, embattled coronet. Address as "Your Excellency."
Territorial Baron or Baroness - wears simple gold coronet with six spheroids. Address as "Your Excellency."
Court Baron/Baroness - wears simple silver coronet with six spheroids. Address as "Your Excellency."
Knight - wears white belt, gold chain and spurs. Address as "Sir."
Master/Mistress at Arms - wears white baldric and spurs. Address as "Master/Mistress."
Laurel - wears a gold medallion with a green laurel wreath. Address as "Master" or "Mistress."
Pelican - wears a gold medallion with a pelican. Address as "Master or Mistress."
For everyone else, if you know that person has an Award of Arms, address them as "Lord" or "Lady." If you do not know, like most people, simply address everyone with the always courteous "m'lord" or "m'lady" and you can hardly go wrong.