Incorrect Google Caching Suggests a Different Canonical Has Been Chosen
If the cached content from a different page is displayed on a page, this could be because Google has determined that the two pages are duplicates and has canonicalised one to the other.
You Can See Which Canonical Google Has Chosen in the New Search Console
In the new Search Console you can select individual URLs which takes you to the info query showing you the canonical that Google has chosen.
Canonicals Are Chosen by Google Using XML Sitemap URLs
XML sitemap URLs are used to help inform Google’s decision on which URL is chosen to be the canonical.
Mobile Pages Must be Canonicalised to their Desktop Equivalents
If the desktop and mobile versions of a page both appear it means that Google doesn’t understand the connection between them. Make sure the mobile page has a canonical tag to the desktop page.
Rel Canonical Isn’t Required For Paginated Pages
If pagination is added to a page with rel next and rel previous it isn�۪t necessary to add a rel canonical to the page itself but it’s good practice.
Content on Canonicalised Paginated Pages Will Be Lost
Unique content and links on canonicalised paginated pages will be lost if Google accepts the canonical directive.
Update Internal Links to Canonical URLs
Update internal links to canonical URLs to give Google a clean signal about which URL to index. If the canonical is accepted, any links to canonicalised URLs will be associated with the canonical URL.
Low Proportion of Indexed Pages Points to Technical Issue
If a site has a low proportion of indexed pages, this usually points to a technical issue than a quality issue. Compare the site map index counts and index status report for differences. Try splitting up sitemap file , checking indexed pages using info: query, that rel canonicals match those in sitemap file, hreflang and internal linking. Also, uppercase, lowercase, trailing slashes all matter. Then check crawl stats to get idea of crawl rate and if it’s reasonable.
Align Linking & Rel Canonical If Want Particular Page Indexed
Ensure internal links and rel canonical are pointing to preferred page to ensure you aren’t giving Google conflicting signals about which page should be indexed.