This section discusses how to start building a custom theme.
A good practice during development on Magento is to disable Magento’s cache. Although doing this adversely impacts performance, it frees you from having to manually clear the cache when you make changes to files or configuration settings that are being cached. Check Magento Configuration > Cache Management.
You should always enable the cache in a production environment.
The correct way to customize the theme in Magento is to create your own sub-theme. You should never edit original design package files. Files that need to be changed can be copied to your custom sub-theme.