QUOTE: ‘To make our results more useful, we’ve begun experiments to make our index mobile-first. Although our search index will continue to be a single index of websites and apps, our algorithms will eventually primarily use the mobile version of a site’s content to rank pages from that site, to understand structured data, and to show snippets from those pages in our results. Of course, while our index will be built from mobile documents, we’re going to continue to build a great search experience for all users, whether they come from mobile or desktop devices.
QUOTE: “Sitemaps are an easy way for webmasters to inform search engines about pages on their sites that are available for crawling. In its simplest form, a Sitemap is an XML file that lists URLs for a site along with additional metadata about each URL (when it was last updated, how often it usually changes, and how important it is, relative to other URLs in the site) so that search engines can more intelligently crawl the site.”
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.
At the moment, I don’t know you, your business, your website, your resources, your competition or your product. Even with all that knowledge, calculating ROI is extremely difficult because ultimately Google decides on who ranks where in its results – sometimes that’s ranking better sites, and sometimes (often) it is ranking sites breaking the rules above yours.

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).

QUOTE: “How do I move from one domain to another domain and try to preserve the rankings as best as possible?…do a 301 permanent redirect to the new location (assuming that you’re you’re moving for all time and eternity so this is the good case for a permanent or 301 redirect if you were planning to undo this later or it’s temporary then you’d use a 302 redirect)…. search engines should be able to follow the trail of all the 301 redirects” Matt Cutts, Google
Keep resources crawlable. Blocking page resources can give Google an incomplete picture of your website. This often happens when your robots.txt file is blocking access to some or all of your page resources. If Googlebot doesn't have access to a page's resources, such as CSS, JavaScript, or images, we may not detect that it's built to display and work well on a mobile browser. In other words, we may not detect that the page is "mobile-friendly," and therefore not properly serve it to mobile searchers.
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.
If you are using Responsive Web Design, use meta name="viewport" tag to tell the browser how to adjust the content. If you use Dynamic Serving, use the Vary HTTP header to signal your changes depending on the user-agent. If you are using separate URLs, signal the relationship between two URLs by  tag with rel="canonical" and rel="alternate" elements.

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.
Another example when the “nofollow" attribute can come handy are widget links. If you are using a third party's widget to enrich the experience of your site and engage users, check if it contains any links that you did not intend to place on your site along with the widget. Some widgets may add links to your site which are not your editorial choice and contain anchor text that you as a webmaster may not control. If removing such unwanted links from the widget is not possible, you can always disable them with “nofollow" attribute. If you create a widget for functionality or content that you provide, make sure to include the nofollow on links in the default code snippet.
Optimizing a website may involve editing its content, adding content, and modifying HTML and associated coding to both increase its relevance to specific keywords and remove barriers to the indexing activities of search engines like Google ,Yahoo etc.[citation needed] Promoting a site to increase the number of backlinks, or inbound links, is another SEO tactic. By May 2015, mobile search had surpassed desktop search.[3]

Important: The Lowest rating is appropriate if all or almost all of the MC on the page is copied with little or no time, effort, expertise, manual curation, or added value for users. Such pages should be rated Lowest, even if the page assigns credit for the content to another source. Important: The Lowest rating is appropriate if all or almost all of the MC on the page is copied with little or no time, effort, expertise, manual curation, or added value for users. Such pages should be rated Lowest, even if the page assigns credit for the content to another source.

Google recommends that all websites use https:// when possible. The hostname is where your website is hosted, commonly using the same domain name that you'd use for email. Google differentiates between the "www" and "non-www" version (for example, "www.example.com" or just "example.com"). When adding your website to Search Console, we recommend adding both http:// and https:// versions, as well as the "www" and "non-www" versions.

SEO techniques can be classified into two broad categories: techniques that search engine companies recommend as part of good design ("white hat"), and those techniques of which search engines do not approve ("black hat"). The search engines attempt to minimize the effect of the latter, among them spamdexing. Industry commentators have classified these methods, and the practitioners who employ them, as either white hat SEO, or black hat SEO.[50] White hats tend to produce results that last a long time, whereas black hats anticipate that their sites may eventually be banned either temporarily or permanently once the search engines discover what they are doing.[51]

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!
It is important you spread all that real ‘PageRank’ – or link equity – to your sales keyword / phrase rich sales pages, and as much remains to the rest of the site pages, so Google does not ‘demote’ pages into oblivion –  or ‘supplemental results’ as we old timers knew them back in the day. Again – this is slightly old school – but it gets me by, even today.
QUOTE: “I’ve got a slide here where I show I think 8 different URLs you know every single one of these URLs could return completely different content in practice we as humans whenever we look at ‘www.example.com’ or just regular ‘example.com’ or example.com/index or example.com/home.asp we think of it as the same page and in practice it usually is the same page so technically it doesn’t have to be but almost always web servers will return the same content for like these 8 different versions of the URL so that can cause a lot of problems in search engines if rather than having your backlinks all go to one page instead it’s split between (the versions) and it’s a really big headache….how do people fix this well …. the canonical link element” Matt Cutts, Google
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, http://www.example.com and http://example.com). The preferred domain is the version that you want used for your site in the search results.” Google, 2018
Creating high quality content takes a significant amount of at least one of the following: time, effort, expertise, and talent/skill. Content should be factually accurate, clearly written, and comprehensive. So, for example, if you describe your page as a recipe, provide a complete recipe that is easy to follow, rather than just a set of ingredients or a basic description of the dish.
QUOTE: “As the Googlebot does not see [the text in the] the images directly, we generally concentrate on the information provided in the “alt” attribute. Feel free to supplement the “alt” attribute with “title” and other attributes if they provide value to your users! So for example, if you have an image of a puppy (these seem popular at the moment ) playing with a ball, you could use something like “My puppy Betsy playing with a bowling ball” as the alt-attribute for the image. If you also have a link around the image, pointing a large version of the same photo, you could use “View this image in high-resolution” as the title attribute for the link.”

To avoid undesirable content in the search indexes, webmasters can instruct spiders not to crawl certain files or directories through the standard robots.txt file in the root directory of the domain. Additionally, a page can be explicitly excluded from a search engine's database by using a meta tag specific to robots (usually ). When a search engine visits a site, the robots.txt located in the root directory is the first file crawled. The robots.txt file is then parsed and will instruct the robot as to which pages are not to be crawled. As a search engine crawler may keep a cached copy of this file, it may on occasion crawl pages a webmaster does not wish crawled. Pages typically prevented from being crawled include login specific pages such as shopping carts and user-specific content such as search results from internal searches. In March 2007, Google warned webmasters that they should prevent indexing of internal search results because those pages are considered search spam.[47]

Yes, you need to build links to your site to acquire more PageRank, or Google ‘juice’ – or what we now call domain authority or trust. Google is a link-based search engine – it does not quite understand ‘good’ or ‘quality’ content – but it does understand ‘popular’ content. It can also usually identify poor, or THIN CONTENT – and it penalises your site for that – or – at least – it takes away the traffic you once had with an algorithm change. Google doesn’t like calling actions the take a ‘penalty’ – it doesn’t look good. They blame your ranking drops on their engineers getting better at identifying quality content or links, or the inverse – low-quality content and unnatural links. If they do take action your site for paid links – they call this a ‘Manual Action’ and you will get notified about it in Webmaster Tools if you sign up.
You should build a website to benefit your users, and any optimization should be geared toward making the user experience better. One of those users is a search engine, which helps other users discover your content. Search Engine Optimization is about helping search engines understand and present content. Your site may be smaller or larger than our example site and offer vastly different content, but the optimization topics we discuss below should apply to sites of all sizes and types. We hope our guide gives you some fresh ideas on how to improve your website, and we'd love to hear your questions, feedback, and success stories in the Google Webmaster Help Forum1.