In Dragon Age 2 for the PS3, Xbox 360, and PC, there is a really easy way to get an unlimited amount of XP in the game using a quest glitch.
On any quest that doesn’t have a cut-scene when you turn it in, simply draw your weapon out before you speak to the quest giver to turn in your quest. After your character automatically puts their weapon away, keep hitting the A button to keep receiving XP, and any gold that the quest provides as well.
This may be (and most likely will be) patched in the future, so avoid installing any game updates if you want to continue using this glitch.