Provide full functionality on all devices. Mobile users expect the same functionality - such as commenting and check-out - and content on mobile as well as on all other devices that your website supports. In addition to textual content, make sure that all important images and videos are embedded and accessible on mobile devices. For search engines, provide all structured data and other metadata - such as titles, descriptions, link-elements, and other meta-tags - on all versions of the pages.
Google decides which pages on your site are important or most relevant. You can help Google by linking to your important pages and ensuring at least one page is well optimised amongst the rest of your pages for your desired key phrase. Always remember Google does not want to rank ‘thin’ pages in results – any page you want to rank – should have all the things Google is looking for. That’s a lot these days!
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.
Google is a link-based search engine. Google doesn’t need content to rank pages but it needs content to give to users. Google needs to find content and it finds content by following links just like you do when clicking on a link. So you need first to make sure you tell the world about your site so other sites link to yours. Don’t worry about reciprocating to more powerful sites or even real sites – I think this adds to your domain authority – which is better to have than ranking for just a few narrow key terms.
Description meta tags are important because Google might use them as snippets for your pages. Note that we say "might" because Google may choose to use a relevant section of your page's visible text if it does a good job of matching up with a user's query. Adding description meta tags to each of your pages is always a good practice in case Google cannot find a good selection of text to use in the snippet. The Webmaster Central Blog has informative posts on improving snippets with better description meta tags18 and better snippets for your users19. We also have a handy Help Center article on how to create good titles and snippets20.

While that theory is sound (when focused on a single page, when the intent is to deliver utility content to a Google user) using old school SEO techniques on especially a large site spread out across many pages seems to amplify site quality problems, after recent algorithm changes, and so this type of optimisation without keeping an eye on overall site quality is self-defeating in the long run.
Structured data21 is code that you can add to your sites' pages to describe your content to search engines, so they can better understand what's on your pages. Search engines can use this understanding to display your content in useful (and eye-catching!) ways in search results. That, in turn, can help you attract just the right kind of customers for your business.

Don’t break Google’s trust – if your friend betrays you, depending on what they’ve done, they’ve lost trust. Sometimes that trust has been lost altogether. If you do something Google doesn’t like such as manipulate it in a way it doesn’t want, you will lose trust, and in some cases, lose all trust (in some areas). For instance, your pages might be able to rank, but your links might not be trusted enough to vouch for another site. DON’T FALL OUT WITH GOOGLE OVER SOMETHING STUPID
This helpful tool scans your backlink profile and turns up a list of contact information for the links and domains you'll need to reach out to for removal. Alternatively, the tool also allows you to export the list if you wish to disavow them using Google's tool. (Essentially, this tool tells Google not to take these links into account when crawling your site.)
Think, that one day, your website will have to pass a manual review by ‘Google’ – the better rankings you get, or the more traffic you get, the more likely you are to be reviewed. Know that Google, at least classes even useful sites as spammy, according to leaked documents. If you want a site to rank high in Google – it better ‘do’ something other than exist only link to another site because of a paid commission. Know that to succeed, your website needs to be USEFUL, to a visitor that Google will send you – and a useful website is not just a website, with a sole commercial intent, of sending a visitor from Google to another site – or a ‘thin affiliate’ as Google CLASSIFIES it.
I think ranking in organic listings is a lot about trusted links making trusted pages rank, making trusted links making trusted pages rank ad nauseam for various keywords. Some pages can pass trust to another site; some pages cannot. Some links can. Some cannot. Some links are trusted enough to pass ranking signals to another page. Some are not. YOU NEED LINKS FROM TRUSTED PAGES IF YOU WANT TO RANK AND AVOID PENALTIES & FILTERS.
QUOTE: “We do use it for ranking, but it’s not the most critical part of a page. So it’s not worthwhile filling it with keywords to hope that it works that way. In general, we try to recognise when a title tag is stuffed with keywords because that’s also a bad user experience for users in the search results. If they’re looking to understand what these pages are about and they just see a jumble of keywords, then that doesn’t really help.” John Mueller, Google 2016
The world is mobile today. Most people are searching on Google using a mobile device. The desktop version of a site might be difficult to view and use on a mobile device. As a result, having a mobile ready site is critical to your online presence. In fact, starting in late 2016, Google has begun experiments to primarily use the mobile version of a site's content42 for ranking, parsing structured data, and generating snippets.
Webmasters and content providers began optimizing websites for search engines in the mid-1990s, as the first search engines were cataloging the early Web. Initially, all webmasters only needed to submit the address of a page, or URL, to the various engines which would send a "spider" to "crawl" that page, extract links to other pages from it, and return information found on the page to be indexed.[5] The process involves a search engine spider downloading a page and storing it on the search engine's own server. A second program, known as an indexer, extracts information about the page, such as the words it contains, where they are located, and any weight for specific words, as well as all links the page contains. All of this information is then placed into a scheduler for crawling at a later date.
OBSERVATION – You can have the content and the links – but if your site falls short on even a single user satisfaction signal (even if it is picked up by the algorithm, and not a human reviewer) then your rankings for particular terms could collapse – OR – rankings can be held back – IF Google thinks your organisation, with its resources, or ‘reputation, should be delivering a better user experience to users.
QUOTE: “Starting April 21 (2015), we will be expanding our use of mobile-friendliness as a ranking signal. This change will affect mobile searches in all languages worldwide and will have a significant impact in our search results. Consequently, users will find it easier to get relevant, high-quality search results that are optimized for their devices”. GOOGLE

On October 17, 2002, SearchKing filed suit in the United States District Court, Western District of Oklahoma, against the search engine Google. SearchKing's claim was that Google's tactics to prevent spamdexing constituted a tortious interference with contractual relations. On May 27, 2003, the court granted Google's motion to dismiss the complaint because SearchKing "failed to state a claim upon which relief may be granted."[68][69]
In December 2009, Google announced it would be using the web search history of all its users in order to populate search results.[33] On June 8, 2010 a new web indexing system called Google Caffeine was announced. Designed to allow users to find news results, forum posts and other content much sooner after publishing than before, Google caffeine was a change to the way Google updated its index in order to make things show up quicker on Google than before. According to Carrie Grimes, the software engineer who announced Caffeine for Google, "Caffeine provides 50 percent fresher results for web searches than our last index..."[34] Google Instant, real-time-search, was introduced in late 2010 in an attempt to make search results more timely and relevant. Historically site administrators have spent months or even years optimizing a website to increase search rankings. With the growth in popularity of social media sites and blogs the leading engines made changes to their algorithms to allow fresh content to rank quickly within the search results.[35]
If you link out to irrelevant sites, Google may ignore the page, too – but again, it depends on the site in question. Who you link to, or HOW you link to, REALLY DOES MATTER – I expect Google to use your linking practices as a potential means by which to classify your site. Affiliate sites, for example, don’t do well in Google these days without some good quality backlinks and higher quality pages.
Tablet - We consider tablets as devices in their own class, so when we speak of mobile devices, we generally do not include tablets in the definition. Tablets tend to have larger screens, which means that, unless you offer tablet-optimized content, you can assume that users expect to see your site as it would look on a desktop browser rather than on a smartphone browser.
This broken-link checker makes it easy for a publisher or editor to make corrections before a page is live. Think about a site like Wikipedia, for example. The Wikipedia page for the term "marketing" contains a whopping 711 links. Not only was Check My Links able to detect this number in a matter of seconds, but it also found (and highlighted) seven broken links.
The world is mobile today. Most people are searching on Google using a mobile device. The desktop version of a site might be difficult to view and use on a mobile device. As a result, having a mobile ready site is critical to your online presence. In fact, starting in late 2016, Google has begun experiments to primarily use the mobile version of a site's content42 for ranking, parsing structured data, and generating snippets.

Robots.txt is not an appropriate or effective way of blocking sensitive or confidential material. It only instructs well-behaved crawlers that the pages are not for them, but it does not prevent your server from delivering those pages to a browser that requests them. One reason is that search engines could still reference the URLs you block (showing just the URL, no title or snippet) if there happen to be links to those URLs somewhere on the Internet (like referrer logs). Also, non-compliant or rogue search engines that don't acknowledge the Robots Exclusion Standard could disobey the instructions of your robots.txt. Finally, a curious user could examine the directories or subdirectories in your robots.txt file and guess the URL of the content that you don't want seen.