Prefixes:
Abbreviations can be used for Mr., Mrs., Ms and Dr. Titles for clergy, judges, and military officers should be written out in full:
Mr. David Smith
Dr. and Mrs. Smith
The Doctors Smith
The Reverend David Smith
Captain David Smith
Second Lieutenant,
United States Navy
(name first, then title, then rank and branch of service)
Suffixes:
Junior is preceded by a comma, and when spelled out
and not capitalized:
Mr. David Smith, junior
Roman numerals are preceded by a comma:
Mr. David Smith, III