Part of knowing what to do in keeping your joomla hosting secure is making sure you know what NOT to do. Here are five important donts:
1. Dont upgrade on a live website. You need to test your upgrades every time you run the site on them for the first time to check for bugs and other potential problems.
2. Dont trust third party extensions. Not all third party software is malicious, but its really up to you if you want to take that risk. Of course, if you know and trust the source of the extension, then you can obviously make that an exception.
3. Dont forget to update your version of Joomla hosting. Updates include added protection on the software. Update your Joomla whenever its available, ASAP.
4. Dont give out sensitive information on the forums when you report a security breach. People tend to panic and rant whenever something like this happens, but panicking will only make you open to more attacks.