Throughout the movie you see Sylvester Stallone's character putting a special oil on his hands from time to time. This is done by many card magicians (not just cardsharps) to keep the hands soft so that you can manipulate the cards easier.
The book shown throughout the movie, "The Expert at the Card Table" by S.W. Erdnase, is known as the "Cardman's Bible". Originally published in 1902 for cheating purposes, it is still considered the best book on card manipulation. It is a quote of Erdnase which is shown onscreen as the film begins.
At the final game, when the camera looks at Vernon, we see Tiffany smoking behind him, apart from Miller. But when the camera shows Tiffany herself, we see she's right beside Miller.
In the final hand, the Dean tells Vernon to show his hole card. However, Dean was called so he should show first. Later Dean says that he could buy the pot for an additional $10 bet but at that point betting is closed.