Great article. Do you use some tools that generate the best-ranking keywords, and if so, which ones? Also, once you hire someone to optimize your website, does it mean that you don’t have to change it ever again? I’m asking because I see that a lot of SEO techniques are outdated and not only do they become useless, they can even harm you. Is that true?
You can confer some of your site's reputation to another site when your site links to it. Sometimes users can take advantage of this by adding links to their own site in your comment sections or message boards. Or sometimes you might mention a site in a negative way and don't want to confer any of your reputation upon it. For example, imagine that you're writing a blog post on the topic of comment spamming and you want to call out a site that recently comment spammed your blog. You want to warn others of the site, so you include the link to it in your content; however, you certainly don't want to give the site some of your reputation from your link. This would be a good time to use nofollow.
You may not want certain pages of your site crawled because they might not be useful to users if found in a search engine's search results. If you do want to prevent search engines from crawling your pages, Google Search Console has a friendly robots.txt generator to help you create this file. Note that if your site uses subdomains and you wish to have certain pages not crawled on a particular subdomain, you'll have to create a separate robots.txt file for that subdomain. For more information on robots.txt, we suggest this Webmaster Help Center guide on using robots.txt files13.
Experience can educate you when a page is high-quality and yet receives no traffic. If the page is thin, but is not manipulative, is indeed ‘unique’ and delivers on a purpose with little obvious detectable reason to mark it down, then you can say it is a high-quality page – just with very little search demand for it. Ignored content is not the same as ‘toxic’ content.
And so on and so on. The point of this step isn't to come up with your final list of keyword phrases. You just want to end up with a brain dump of phrases you think potential customers might use to search for content related to that particular topic bucket. We'll narrow the lists down later in the process so you don't have something too unwieldy. Once you have your final list, there are several data-driven tools available to you for finding out which keywords you're most likely to rank well for. 
QUOTE: “They follow the forms you gather data you do so and so and so forth but they don’t get any laws they don’t haven’t found out anything they haven’t got anywhere yet maybe someday they will but it’s not very well developed but what happens is an even more mundane level we get experts on everything that sound like this sort of scientific expert they they’re not scientist is a typewriter and they make up something.”  Richard Feynman, Physicist
QUOTE: “If you want to stop spam, the most straight forward way to do it is to deny people money because they care about the money and that should be their end goal. But if you really want to stop spam, it is a little bit mean, but what you want to do, is sort of break their spirits. There are lots of Google algorithms specifically designed to frustrate spammers. Some of the things we do is give people a hint their site will drop and then a week or two later, their site actually does drop. So they get a little bit more frustrated. So hopefully, and we’ve seen this happen, people step away from the dark side and say, you know what, that was so much pain and anguish and frustration, let’s just stay on the high road from now on.” Matt Cutts, Google 2013
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.
Off-page SEO builds a website’s reputation and authority by connecting it to other high-quality websites. Off-page SEO techniques include: link building (acquiring high-quality backlinks) from other websites and managing local listings and directory profiles. When many websites link to a brand’s website, it shows search engines that the brand’s website is trustworthy, reliable, and reputable, which increases its search rankings.

QUOTE: “So sites that don’t have much content “above-the-fold” can be affected by this change. If you click on a website and the part of the website you see first either doesn’t have a lot of visible content above-the-fold or dedicates a large fraction of the site’s initial screen real estate to ads, that’s not a very good user experience.” Google 2012
QUOTE: “Medium pages achieve their purpose and have neither high nor low expertise, authoritativeness, and trustworthiness. However, Medium pages lack the characteristics that would support a higher quality rating. Occasionally, you will find a page with a mix of high and low quality characteristics. In those cases, the best page quality rating may be Medium.” Google Quality Evaluator Guidelines, 2017
A breadcrumb is a row of internal links at the top or bottom of the page that allows visitors to quickly navigate back to a previous section or the root page. Many breadcrumbs have the most general page (usually the root page) as the first, leftmost link and list the more specific sections out to the right. We recommend using breadcrumb structured data markup28 when showing breadcrumbs.
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.