Open up your php.ini file and scroll down to where it says:
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Error handling and logging ;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
Change:
error_reporting =
To whatever value you would like, it shows examples above it.
Also Change:
display_errors = Off
To:
display_errors = On
That should do it. Just give Apache a good restart and everything should work to your liking.