Cliches. Things that shouldn't be done.

Things such as betting more than money -your house, watch and so on- must be avoided. I watched a few short films on poker that deal with pretty much the same thing all of them, someone losing all of his money, someone getting killed because he owes money, a lack of story on most of them, no real focus and work on characters and a strong sense of "i've seen this before" on all of them.