WARNING: On your production server you should never have to do this unless there is absolutely no other choice. Use the log files instead.
Warning: Do not do this unless you really know what you are doing.
On your staging server, turning on debugging helps you check new plugin installs, debug issues with your theme or other custom work that you have implemented.
Site administration > Development > Debugging
- Set Debug messages to DEVELOPER.
- Set Display debug messages to True.
This will show all issues and errors and is invaluable in troubleshooting issues.
MAKE SURE YOU SWITCH DEBUGGING BACK OFF WHEN YOU HAVE FINISHED CHECKING ERRORS.