Mamet wrote the part of Jimmy Dell specifically for Steve Martin in order to take full advantage from the comic playing against type. He was one of the first to recognize that Martin, renowned for his manic energy, possessed a deep well of seriousness which allowed Martin to portray his character as calm and in charge, which in turn made him appear menacing.
When he is hung over, George Lang says, "I put a thief in my mouth to steal my brains." The line is a close paraphrase of one from Shakespeare's "Othello": "I would not put a thief in my mouth to steal my brains."
The very first shot of the movie contains the curative advice that could have prevented the con from being effective. Joe is seen at the airport standing under the sign that warns passengers to not take packages from anyone.
George Lang's line "Beware of all enterprises which require new clothes" is by Thoreau ("Economy" chapter of Walden).
During the scene in the airport near the end of the film, the fussy child drops his book in front of Joe (Campbell Scott). The book is "The Giving Tree" by the late Shel Silverstein. Silverstein was a close friend of Mamet's and the two co-wrote the film Wo bitte geht's zum Knast (1988).