If you lose a lot of money, press CTRL + ALT + DELETE and close the game. It will not save and when you return to the tournament it will resume from the last game you saved. If you win tons of money, it is a good idea to exit to the main menu. The game will be saved there.
While playing a 5 Card Draw unlimited tournament, take everyone's money before the round ends during the first two rounds. When the second round (when no one else has money remaining) ends, exit to the main menu then re-enter the tournament. It will start in the third round, but you will instantly win the tournament.