Developing a new Joomla template on a test site and then transferring it and making it the new template on your live Joomla site can be a real pain.

How to Develop and Hot Swap Joomla Templates on Live Joomla SitesThis Joomla tutorial shows a way to develop and test a new template for your Joomla site right on the live site without anyone noticing. That way you can hot swap the new template right on your live Joomla site when it is completed to your liking.