How to see the error messages when I get the white screen of death? How can I see the error messages when the site I am working on gets a white screen?
Put this at the bottom of settings.php:

error_reporting(-1);  // Have PHP complain about absolutely everything 
$conf['error_level'] = 2;  // Show all messages on your screen, 2 = ERROR_REPORTING_DISPLAY_ALL.
ini_set('display_errors', TRUE);  // These lines just give you content on WSOD pages.
ini_set('display_startup_errors', TRUE);