Changes to wp-config.php
Copy/paste some or all of these lines into your wp-config.php
define('WP_DEBUG',true);
define('WP_DEBUG_DISPLAY', false);
// Go look for $_DOCROOT/wp-content/debug.log
define('WP_DEBUG_LOG', true);
define( 'SCRIPT_DEBUG', true );
define( 'SAVEQUERIES', true );
Plugins that can help with debugging
These plugins can help you get more information without having to go into a terminal.