Expertise and authoritativeness of a site increases its quality. Be sure that content on your site is created or edited by people with expertise in the topic. For example, providing expert or experienced sources can help users understand articles’ expertise. Representing well-established consensus in pages on scientific topics is a good practice if such consensus exists.

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.
Try and get links within page text pointing to your site with relevant, or at least, natural looking, keywords in the text link – not, for instance, in blogrolls or site-wide links. Try to ensure the links are not obviously “machine generated” e.g. site-wide links on forums or directories. Get links from pages, that in turn, have a lot of links to them, and you will soon see benefits.
Google knows who links to you, the “quality” of those links, and whom you link to. These – and other factors – help ultimately determine where a page on your site ranks. To make it more confusing – the page that ranks on your site might not be the page you want to rank, or even the page that determines your rankings for this term. Once Google has worked out your domain authority – sometimes it seems that the most relevant page on your site Google HAS NO ISSUE with will rank.
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.
The transparency you provide on your website in text and links about who you are, what you do, and how you’re rated on the web or as a business is one way that Google could use (algorithmically and manually) to ‘rate’ your website. Note that Google has a HUGE army of quality raters and at some point they will be on your site if you get a lot of traffic from Google.

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 states, “News articles, Wikipedia articles, blog posts, magazine articles, forum discussions, and ratings from independent organizations can all be sources of reputation information” but they also state specifically boasts about a lot of internet traffic, for example, should not influence the quality rating of a web page. What should influence the reputation of a page is WHO has shared it on social media etc. rather than just raw numbers of shares. CONSIDER CREATING A PAGE with nofollow links to good reviews on other websites as proof of excellence.
In March 2006, KinderStart filed a lawsuit against Google over search engine rankings. KinderStart's website was removed from Google's index prior to the lawsuit, and the amount of traffic to the site dropped by 70%. On March 16, 2007, the United States District Court for the Northern District of California (San Jose Division) dismissed KinderStart's complaint without leave to amend, and partially granted Google's motion for Rule 11 sanctions against KinderStart's attorney, requiring him to pay part of Google's legal expenses.[70][71]
I’ve got by, by thinking external links to other sites should probably be on single pages deeper in your site architecture, with the pages receiving all your Google Juice once it’s been “soaked up” by the higher pages in your site structure (the home page, your category pages). This tactic is old school but I still follow it. I don’t need to think you need to worry about that, too much, in 2019.

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.
Redirecting is the act of sending a user to a different URL than the one initially requested. There are many good reasons to redirect from one URL to another, for example, when a website moves to a new address. However, some redirects are designed to deceive search engines and users. These are a very poor user experience, and users may feel tricked or confused. We will call these “sneaky redirects.” Sneaky redirects are deceptive and should be rated Lowest.
The above information does not need to feature on every page, more on a clearly accessible page. However – with Google Quality Raters rating web pages on quality based on Expertise, Authority and Trust (see my recent making high-quality websites post) – ANY signal you can send to an algorithm or human reviewer’s eyes that you are a legitimate business is probably a sensible move at this time (if you have nothing to hide, of course).
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.
QUOTE: “Ultimately, you just want to have a really great site people love. I know it sounds like a cliché, but almost [all of] what we are looking for is surely what users are looking for. A site with content that users love – let’s say they interact with content in some way – that will help you in ranking in general, not with Panda. Pruning is not a good idea because with Panda, I don’t think it will ever help mainly because you are very likely to get Panda penalized – Pandalized – because of low-quality content…content that’s actually ranking shouldn’t perhaps rank that well. Let’s say you figure out if you put 10,000 times the word “pony” on your page, you rank better for all queries. What Panda does is disregard the advantage you figure out, so you fall back where you started. I don’t think you are removing content from the site with potential to rank – you have the potential to go further down if you remove that content. I would spend resources on improving content, or, if you don’t have the means to save that content, just leave it there. Ultimately people want good sites. They don’t want empty pages and crappy content. Ultimately that’s your goal – it’s created for your users.” Gary Illyes, Google 2017
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]
When Googlebot crawls a page, it should see the page the same way an average user does15. For optimal rendering and indexing, always allow Googlebot access to the JavaScript, CSS, and image files used by your website. If your site's robots.txt file disallows crawling of these assets, it directly harms how well our algorithms render and index your content. This can result in suboptimal rankings.