There are a lot of definitions of SEO (spelled Search engine optimisation in the UK, Australia and New Zealand, or search engine optimization in the United States and Canada) but organic SEO in 2019 is still mostly about getting free traffic from Google, the most popular search engine in the world (and almost the only game in town in the UK in 2019):

QUOTE: “Shopping or financial transaction pages: webpages which allow users to make purchases, transfer money, pay bills, etc. online (such as online stores and online banking pages)…..We have very high Page Quality rating standards for YMYL pages because low-quality YMYL pages could potentially negatively impact users’ happiness, health, or wealth.“
Naturally, business owners want to rank for lots of keywords in organic listings with their website. The challenge for webmasters and SEO is that Google doesn’t want business owners to rank for lots of keywords using autogenerated content especially when that produces A LOT of pages on a website using (for instance) a list of keyword variations page-to-page.

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.
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]
The more important concept to keep in mind is that you want to choose keywords that best relate to the content present on a web page and on a website; if you don't have a dog food comparison matrix, then don't bother including comparison-related keywords; you are misleading your users, and certainly not fooling Google. So in an ideal world, you do have a comparison section, a reviews section, and a rankings section, housed on different pages or sections of your site, with each one tagged with the appropriate keywords. Correspondingly, your SEO and PPC search engine marketing efforts should that content by driving review keywords to the review pages and so on.
QUOTE:  Each piece of duplication in your on-page SEO strategy is ***at best*** wasted opportunity. Worse yet, if you are aggressive with aligning your on page heading, your page title, and your internal + external link anchor text the page becomes more likely to get filtered out of the search results (which is quite common in some aggressive spaces). Aaron Wall, 2009

Did you know that nearly 60% of the sites that have a top ten Google search ranking are three years old or more? Data from an Ahrefs study of two million pages suggests that very few sites less than a year old achieve that ranking. So if you’ve had your site for a while, and have optimized it using the tips in this article, that’s already an advantage.

Starting with the search term dog food, I see related more specific terms like dog food reviews, dog food comparison, and dog food brands, which can help identify other keywords to focus on. Then, clicking on dog food brands, the search engine automatically expands that keyword to be another hub, with more specific keywords related to dog food brands such as nutro dog food, Purina dog food, and so on.
In Chapter 2, we learned about SERP features. That background is going to help us understand how searchers want to consume information for a particular keyword. The format in which Google chooses to display search results depends on intent, and every query has a unique one. Google describes these intents in their Quality Rater Guidelines as either “know” (find information), “do” (accomplish a goal), “website” (find a specific website), or “visit-in-person” (visit a local business).

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]
An SEO meta description is a brief description of content found on a web page. The meta description is shown to users in search engine results pages to help them decide which search result to click on. Meta descriptions are not a ranking factor in the eyes of a search engine, but they can influence how many people click on a result -- which directly affects the result's organic ranking.
Some pages are designed to manipulate users into clicking on certain types of links through visual design elements, such as page layout, organization, link placement, font color, images, etc. We will consider these kinds of pages to have deceptive page design. Use the Lowest rating if the page is deliberately designed to manipulate users to click on Ads, monetized links, or suspect download links with little or no effort to provide helpful MC.
As keywords define each page of your site, you can use them to organize your content and formulate a strategy. The most basic way to do this is to start a spreadsheet (your "content to keyword map") and identify your primary keyword for each article. You can then build your sheet to your own requirements, add keyword search volume, organic traffic, page authority and any other metrics that are important to your business.