Forget whether or not to put your keyword in it, make it relevant to a searcher and write it for humans, not search engines. If you want to have this 20-word meta description which accurately describes the page you have optimised (for one or two keyword phrases) when people use Google to search, make sure the keyword is in there. There is more likelihood it will be used by Google as your snippet description in SERPs.
QUOTE:  “Tell visitors clearly that the page they’re looking for can’t be found. Use language that is friendly and inviting. Make sure your 404 page uses the same look and feel (including navigation) as the rest of your site. Consider adding links to your most popular articles or posts, as well as a link to your site’s home page. Think about providing a way for users to report a broken link. No matter how beautiful and useful your custom 404 page, you probably don’t want it to appear in Google search results. In order to prevent 404 pages from being indexed by Google and other search engines, make sure that your webserver returns an actual 404 HTTP status code when a missing page is requested.” Google, 2018
Comparing your Google Analytics data side by side with the dates of official algorithm updates is useful in diagnosing a site health issue or traffic drop. In the above example, a new client thought it was a switch to HTTPS and server downtime that caused the drop when it was actually the May 6, 2015, Google Quality Algorithm (originally called Phantom 2 in some circles) that caused the sudden drop in organic traffic – and the problem was probably compounded by unnatural linking practices. (This client did eventually receive a penalty for unnatural links when they ignored our advice to clean up).

While Google is on record as stating these quality raters do not directly influence where you rank (without more senior analysts making a call on the quality of your website, I presume?) – there are some things in this document, mostly of a user experience nature (UX) that all search engine optimisers and Webmasters of any kind should note going forward.

Onsite, consider linking to your other pages by linking to pages within main content text. I usually only do this when it is relevant – often, I’ll link to relevant pages when the keyword is in the title elements of both pages. I don’t go in for auto-generating links at all. Google has penalised sites for using particular auto link plugins, for instance, so I avoid them.
QUOTE: “So if you have different parts of your website and they’re on different subdomains that’s that’s perfectly fine that’s totally up to you and the way people link across these different subdomains is really up to you I guess one of the tricky aspects there is that we try to figure out what belongs to a website and to treat that more as a single website and sometimes things on separate subdomains are like a single website and sometimes they’re more like separate websites for example on on blogger all of the subdomains are essentially completely separate websites they’re not related to each other on the other hand other websites might have different subdomains and they just use them for different parts of the same thing so maybe for different country versions maybe for different language versions all of that is completely normal.” John Mueller 2017
Ever since its April 2015 update, Google is now taking the user's mobile experience into consideration in its search results. This means that when a user is doing a search on a mobile device, Google's search results will favor websites that are mobile friendly over the ones that aren't. If you want to capture that mobile search audience, you will need to have a mobile version of your website in addition to your desktop version.
Google will select the best title it wants for your search snippet – and it will take that information from multiple sources, NOT just your page title element. A small title is often appended with more information about the domain. Sometimes, if Google is confident in the BRAND name, it will replace it with that (often adding it to the beginning of your title with a colon, or sometimes appending the end of your snippet title with the actual domain address the page belongs to).

The errors in technical SEO are often not obvious, and therefore one of the most popular. Mistakes in robots.txt and 404 pages, pagination and canonical URLs, hreflang tags and 301 redirects, http vs https and www vs non www versions: each of them can seriously spoil all efforts to promote the site. One quality SEO website analysis is enough to solve all the main problems in this part forever.
While most of the links to your site will be added gradually, as people discover your content through search or other ways and link to it, Google understands that you'd like to let others know about the hard work you've put into your content. Effectively promoting your new content will lead to faster discovery by those who are interested in the same subject. As with most points covered in this document, taking these recommendations to an extreme could actually harm the reputation of your site.

Google will INDEX perhaps 1000s of characters in a title… but I don’t think anyone knows exactly how many characters or words Google will count AS a TITLE TAG when determining RELEVANCE OF A DOCUMENT for ranking purposes. It is a very hard thing to try to isolate accurately with all the testing and obfuscation Google uses to hide it’s ‘secret sauce’. I have had ranking success with longer titles – much longer titles. Google certainly reads ALL the words in your page title (unless you are spamming it silly, of course).
QUOTE: “The preferred domain is the one that you would liked used to index your site’s pages (sometimes this is referred to as the canonical domain). Links may point to your site using both the www and non-www versions of the URL (for instance, and The preferred domain is the version that you want used for your site in the search results.” Google, 2018
Think about how Google can algorithmically and manually determine the commercial intent of your website – think about the signals that differentiate a real small business website from a website created JUST to send visitors to another website with affiliate links, on every page, for instance; or adverts on your site, above the fold, etc, can be a clear indicator of a webmaster’s particular commercial intent – hence why Google has a Top Heavy Algorithm.
QUOTE: “Supplementary Content contributes to a good user experience on the page, but does not directly help the page achieve its purpose. SC is created by Webmasters and is an important part of the user experience. One common type of SC is navigation links which allow users to visit other parts of the website. Note that in some cases, content behind tabs may be considered part of the SC of the page.” Google Search Quality Evaluator Guidelines 2017
I think it makes sense to have unique content as much as possible on these pages but it’s not not going to like sync the whole website if you don’t do that we don’t penalize a website for having this kind of deep duplicate content and kind of going back to the first thing though with regards to doorway pages that is something I definitely look into to make sure that you’re not running into that so in particular if this is like all going to the same clinic and you’re creating all of these different landing pages that are essentially just funneling everyone to the same clinic then that could be seen as a doorway page or a set of doorway pages on our side and it could happen that the web spam team looks at that and says this is this is not okay you’re just trying to rank for all of these different variations of the keywords and the pages themselves are essentially all the same and they might go there and say we need to take a manual action and remove all these pages from search so that’s kind of one thing to watch out for in the sense that if they are all going to the same clinic then probably it makes sense to create some kind of a summary page instead whereas if these are going to two different businesses then of course that’s kind of a different situation it’s not it’s not a doorway page situation.”
A page title that is highly relevant to the page it refers to will maximise usability, search engine ranking performance and user experience ratings as Google measures these. It will probably be displayed in a web browser’s window title bar, bookmarks and in clickable search snippet links used by Google, Bing & other search engines. The title element is the “crown” of a web page with important keyword phrase featuring AT LEAST ONCE within it.
SEO is the practice of optimizing websites to make them reach a high position in Google’s – or another search engine’s – search results. At Yoast, we believe that holistic SEO is the best way to rank your website because you focus on making every aspect of your site awesome. Don’t use any black-hat SEO tricks, because eventually, this will have negative consequences for your rankings. Instead, practice sustainable SEO, with your user in mind, and you will benefit in the long run.