Ten Commandments for Con Men, by "Count" Victor Lustig (1936)

Noted con man Victor Lustig had twenty-five known aliases, spoke five languages, and was wanted by approximately forty-five law enforcement agencies worldwide for a plethora of crimes. These were his commandments.
  1. 1.
    Be a patient listener (it is this, not fast talking, that gets a con-man his coups).
  2. 2.
    Never look bored.
  3. 3.
    Wait for the other person to reveal any political opinions, then agree with them.
  4. 4.
    Let the other person reveal religious views, then have the same ones.
  5. 5.
    Hint at sex talk, but don't follow it up unless the other fellow shows a strong interest.
  6. 6.
    Never discuss illness, unless some special concern is shown.
  7. 7.
    Never pry into a person's personal circumstances (they'll tell you all eventually).
  8. 8.
    Never boast. Just let your importance be quietly obvious.
  9. 9.
    Never be untidy.
  10. 10.
    Never get drunk.