Google is looking for a “website that is well cared for and maintained” so you need to keep content management systems updated, check for broken image links and HTML links. If you create a frustrating user experience through sloppy website maintenance – expect that to be reflected in some way with a lower quality rating. Google Panda October 2014 went for e-commerce pages that were optimised ‘the old way’ and are now classed as ‘thin content’.
Sometimes, Google turns up the dial on demands on ‘quality’, and if your site falls short, a website traffic crunch is assured. Some sites invite problems ignoring Google’s ‘rules’ and some sites inadvertently introduce technical problems to their site after the date of a major algorithm update and are then impacted negatively by later refreshes of the algorithm.
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
Google ranks websites (relevancy aside for a moment) by the number and quality of incoming links to a site from other websites (amongst hundreds of other metrics). Generally speaking, a link from a page to another page is viewed in Google “eyes” as a vote for that page the link points to. The more votes a page gets, the more trusted a page can become, and the higher Google will rank it – in theory. Rankings are HUGELY affected by how much Google ultimately trusts the DOMAIN the page is on. BACKLINKS (links from other websites – trump every other signal.)

Think about the words that a user might search for to find a piece of your content. Users who know a lot about the topic might use different keywords in their search queries than someone who is new to the topic. For example, a long-time football fan might search for [fifa], an acronym for the Fédération Internationale de Football Association, while a new fan might use a more general query like [football playoffs]. Anticipating these differences in search behavior and accounting for them while writing your content (using a good mix of keyword phrases) could produce positive results. Google Ads provides a handy Keyword Planner34 that helps you discover new keyword variations and see the approximate search volume for each keyword. Also, Google Search Console provides you with the top search queries your site appears for and the ones that led the most users to your site in the Performance Report35.

The ranking of your website is partly decided by on-page factors. On-page SEO factors are all those things you can influence from within your actual website. These factors include technical aspects (e.g. the quality of your code and site speed) and content-related aspects, like the structure of your website or the quality of the copy on your website. These are all crucial on-page SEO factors.