Q. How do can I see my Zotero files?

You can see and sort Zotero files on your computer by finding the location of the Zotero directory "zotero.sqlite". The easiest way to do this is to open Zotero and go to your preferences. If you will be deleting or modifying files be sure to close Firefox or Zotero Standalone so that you do not accidently corrupt your Zotero database.

In your preferences go to the Advanced tab, then Files and Folders subtab, then click the Show Data Directory button.

Open the file titled "storage".

Once in the file you can sort by size by going to View, then Sort by, then select Size.

For information on how to see how much storage you are using through Zotero syncing please see this question and answer.