Titles

So, I’m often in an awkward situation in which I’m not sure how I should be addressing someone. Specifically: 

I don’t know whether I should be using their first name or their title. And, if I should use a title, which one. There are several sources of confusion:

  • I don’t know whether a woman prefers Ms., Mrs. or Miss.
  • I don’t know whether they have an academic, theological, or professional title that I should be using rather than the default Mr/Ms/Miss/Mrs
  • They have more than one title, and I don’t know which one they prefer
  • Or, I simply don’t know which degree of formality is appropriate to the situation

Are there any good clues to look for? And is there a polite way to ask?