You can’t force Google to show a specific URL as a sitelink in the SERPs
Sitelinks are additional results that are sometimes shown below a search result in Google.
John clarified that there are no meta tags or structured data that would force or recommend a specific URL to appear as a sitelink in the SERPs. Google’s systems try to figure out what is related or relevant when looking at a web page. He recommended having a good website structure, clear internal links, and to include clear titles to support sitelinks. There is no guarantee that it will yield a sitelink in the search results, but it helps Google to figure out what content is related and to choose a site link based on that information.
It’s not uncommon to see differences across schema validation tools
Users may see a difference in schema validation across tools. This is because the schema.org test is designed to validate all theoretical schemas, whereas the reports in Google Search Console and the Rich Results Test focus only on schema that can have a visible effect on Google search results. It could also be a simple case of the requirements being different across both tools; Google tends to be a little stricter on its requirements than schema.org. If the goal is simply for the marked-up content to appear in Google’s search features, it’s best to follow Google’s own guidelines.
FAQ schema can be used on select questions
It’s possible to pick and choose which elements on a page to markup with structured data / schema. For example, not every question on an FAQ page needs to be marked up with schema if you see no value in doing so. (John does mention later on that for FAQ schema to be valid, the question must be visible on the page.)
It’s not possible to control which images appear in rich snippets
It seems that images are increasingly being used in the rich snippets shown in the SERPs, but there’s currently no way to tell Google which images are preferred for this purpose. The only option is to use the ‘noimageindex’ meta tag on images that you definitely don’t want to appear in snippets, but note that this particular tag will prevent those images from being indexed entirely.
Google Filters ‘Misleading’ Emojis from Snippets
Misleading emojis, such as stars which could look like reviews, may be filtered from snippets, otherwise they try to allow for unusual characters.
Abuse of Schema Policy May Result in a Sitewide Manual Action for the Specific Type of Rich Result
Usually if you go against schema policy, a manual action for the specific type of rich result could be applied for the entire site until a reconsideration process is completed.
Google May Introduce Rich Results Types to One Country First Before Rolling Them Out
With some rich results types Google may introduce them first to one country in order to understand the right approach and how it should be handled, before rolling them out globally.
FAQ & Rich Results May Not Appear Every Time Your Page is Displayed in Search Results
FAQ schema is not guaranteed to appear every time the page is displayed in search results. This is similar to rich results, where Google will look at different factors before showing them. Google also tries to limit the rich result types seen in search results, to prevent them from becoming overloaded.
Rich Snippets Only Displayed in Search Results if Required Conditions Are Met
Google will only show rich snippet results if the required conditions are met. This includes ensuring the markup is technically correct, which you can confirm using a testing tool, as well as making sure it is logically correct. The final requirement is ensuring the website contains quality content so that Google can trust the information that is being provided.