A white screen of death is typically a fatal PHP error, most of the time due to a syntax error. This often sends no errors to the browser.
Some things you can do:
Turn on PHP error_log in your php.ini file and set the error_reporting levels.
http://php.net/manual/en/errorfunc.configuration.php
Error info: http://www.php.net/manual/en/errorfunc.constants.php
Alternatively or in combination you can turn this on in your wp-config as well (from wordpress codex).
http://codex.wordpress.org/Editing_wp-config.php
/**
* This will log all errors notices and warnings to a file called debug.log in
* wp-content only when WP_DEBUG is true
*/
define('WP_DEBUG', true); // false
if (WP_DEBUG) {
define('WP_DEBUG_LOG', true);
define('WP_DEBUG_DISPLAY', false);
@ini_set('display_errors',0);
}
Turn on WordPress debugging and saved queries, (wp debug is same as above example) in your wp-config.php.
define('WP_DEBUG', true);
define('SAVEQUERIES', true);
And install the debug bar, http://wordpress.org/extend/plugins/debug-bar/
I also recommend using something like xDebug,