How do I enable WordPress Debugging?

Debugging.php

How do I enable WordPress Debugging?
In order to enable debugging in WordPress, you will need to add a small code snippet to your wp-config.php file.

This code will prevent error messages from appearing on-screen and instead log them to the /wp-content/debug.log.

/* Switch this value between true and false to enable and disable debugging */
define('WP_DEBUG', true);

/* This will log all errors notices and warnings to a file called debug.log in wp-content only when WP_DEBUG is true */
if (WP_DEBUG) {
    define('WP_DEBUG_LOG', true);
    define('WP_DEBUG_DISPLAY', false);
    @ini_set('display_errors', 0);
    @ini_set('error_reporting', E_ALL & ~E_NOTICE );
    @error_reporting(E_ALL & ~E_NOTICE);
}
Please see the WordPress Codex entry on this topic for more information.