From “Count” Victor Lustig.  Reproduced below from the wiki page. Always good to know especially in this day and age.

1. Be a patient listener (it is this, not fast talking, that gets a con man his coups).

2. Never look bored.

3. Wait for the other person to reveal any political opinions, then agree with them.

4. Let the other person reveal religious views, then have the same ones.

5. Hint at sex talk, but don’t follow it up unless the other person shows a strong interest.

6. Never discuss illness, unless some special concern is shown.

7. Never pry into a person’s personal circumstances (they’ll tell you all eventually).

8. Never boast. Just let your importance be quietly obvious. [The rule against boasting does not always apply in the United States today.]

9. Never be untidy.

10. Never get drunk.