Enabling the Console

For Steam Version:

1. Navigate to: Documents\My Games\Runic Games\Torchlight 2\save\[aWholeBunchOfNumbers]\settings.txt
2. Change CONSOLE :0 to CONSOLE :1
3. (Optional) Change DEBUGMENUS :0 to DEBUGMENUS :1

For Non-Steam Version:

1. Navigate to: Documents\My Games\Runic Games\Torchlight 2\settings.txt
2. Change CONSOLE :0 to CONSOLE :1
3. (Optional) Change DEBUGMENUS :0 to DEBUGMENUS :1

To bring up the console press Insert.
Typing "Help" in the console will give you a list of useful console commands.
If you enabled DEBUGMENUS as well, CTRL+F is a useful command to see FPS, the chunk you're in and other data.