Zotero provides the ability to save references from most library catalogs and databases, and even some regular web pages, with one click. (Zotero publishes a list of compatible sites, and many sites not on this list also work.) If Zotero detects that you're looking at a book or article on a catalog, database, or a site like Amazon.com, LibraryThing or the New York Times, you'll see a book or page icon appear in the address bar of your browser. Just click the icon and Zotero will automatically save the citation.
If you're on a page of search results with many items, you'll see a folder icon instead. Click this to get a list of all the items on the page, and check off the ones you want to save.