As you might expect from a powerful e-commerce system such as Magento, there are tools to help make your job as a Magento theme developer easier. One of the most useful tools for theme developers is Template Path Hints, which tells you where each block's template in your Magento store's page is stored in your Magento theme directories.
To enable this tool, navigate to System | Configuration in your Magento administration panel and change the Current Configuration Scope field's value to your store view's value. In the example in the following screenshot, you can see this being set to Default Store View:
Now, select the Developer tab towards the bottom of the list grouped under ADVANCED:
Expand the Debug panel and you are now presented with a selection of options; set the value for the Template Path Hints field to Yes, as seen in the following screenshot (you may need to uncheck the Use Website checkbox before you can do this):
Tip
For more advanced template hints on Magento theming, see the module available at http://www.fabrizio-branca.de/magento-advanced-template-hints-20.html.
Finally, click on the Save Config button to save these changes, and refresh one of the pages on the frontend of your Magento store to see the tool appear.
It is possible to restrict these hints' display to specific IP addresses too, by expanding the Developer Client Restrictions panel above the Debug panel and entering your IP address in the Allowed IPs (comma separated) field:
Only visitors using the IP address(es) specified in this field will see the debug tools you have enabled once you save this configuration.