You have to flow 2 Steps
Step First :
You have to set cron setting in your admin like below ,
Goto : ADMIN -> SYSTEM -> ADVANCED -> SYSTEM -> Cron (Scheduled Tasks) - all the times are in minutes
set as per your need

AND
set cron file into you Cpanel
Goto Cpanel -> Search " Cron Jobs " -> set you cron file
*/15 * * * * wget -q -O /dev/null /Magento_root_path/cron.php
Step Second :
Just copy Template.php file into below path
/app/code/core/Mage/Core/Model/Email/Template.php
And Make directory like below and paste there.
/app/code/local/Mage/Core/Model/Email/Template.php
Now edit new Template.php and Goto line number : 407
if ($this->hasQueue() && $this->getQueue() instanceof Mage_Core_Model_Email_Queue) {
Update as
if (!($this->hasQueue()) && $this->getQueue() instanceof Mage_Core_Model_Email_Queue) {
Then please clear cache and check.
Hope this will help you.