When working on a Google Site, the view you get as the owner, is sometimes going to be different to the view a visitor gets when they access your website. Google has a built-in option called Preview page as a viewer, to deal with just this problem. It shows you exactly what your Google Site will look like to someone who does not have access to your site as an editor.
Best of all, it is very easy to do. Make sure you are signed in to your Google Site, then click More > Preview page as a viewer, (or use the keyboard shortcut g then p). Your site will then open in a new tab, minus the editing bar you normally see across the top of your page. Instead, you will see a small yellow rectangle at the top of the page that says “Preview page as a viewer”. If you have asked Google to optimize your site for Mobile visitors (More > Manage Site > General > Mobile) you will also see the option to switch to a mobile preview, but in my experience, this is often not a pretty sight!
Why would you want to preview a page as a viewer? Well, if you are anything like me, you may occasionally (read: often!) forget whether or not you changed the sharing settings on an embedded Google document. In the editor view on your site, everything looks fine, and it displays just like it should. However, visitors who do not have access to a document see a placeholder denying them the ability to see it without first requesting access. It is an easy problem to fix, but a quick preview of the site as a viewer can help alleviate problems like this before they arise.