Hey Sharon, great post! Re. dwell time – I’ve read conflicting opinions, some saying that Google DOES consider it an ‘important’ ranking signal, and others saying that it doesn’t, because dwell time can sometimes be a misleading indicator of content quality. For example when a user searches for something specific and finds the answer immediately in the recommended page (meaning that the content on the page is actually spot on) so he returns to the SERPs very quickly. I have been unable to locate any definitive statements (written/spoken) from anyone at Google that suggest that dwell time IS still a factor in ranking considerations, but it makes sense (to me, anyway) that it should be. Do you have any ‘proof’ one way or the other re. whether Google definitely considers dwell time or not?
Make it as easy as possible for users to go from general content to the more specific content they want on your site. Add navigation pages when it makes sense and effectively work these into your internal link structure. Make sure all of the pages on your site are reachable through links, and that they don't require an internal "search" functionality to be found. Link to related pages, where appropriate, to allow users to discover similar content.
QUOTE: “While, as a whole, web usability has improved over these past several years, history repeats and designers make the same mistakes over and over again. Designers and marketers continuously need to walk a line between providing a good user experience and increasing advertising revenue. There is no “correct” answer or golden format for designers to use in order to flawlessly reach audiences; there will inevitably always be resistance to change and a desire for convention and predictability. That said, if, over the course of over ten years, users are still lamenting about the same problems, it’s time we start to take them seriously.”  Therese Fessenden, Nielsen Norman Group 2017
Thanks for the helpful information discussing the differences and similarities between SEO and SEM. The information was enlightening because a search engine optimization company like the one that I own is relatively new at starting. We believe everyone should always check out their sources because every different perspective is very different so all approaches can be understood differently.
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.” John Mueller, Google 2008
QUOTE: “In place of a pop-up try a full-screen inline ad. It offers the same amount of screen real estate as pop-ups without covering up any content. Fixing the problem depends on the issue you have for example if it’s a pop-up you’ll need to remove all the pop-up ads from your site but if the issue is high ad density on a page you’ll need to reduce the number of ads” Google, 2017
Users will occasionally come to a page that doesn't exist on your site, either by following a broken link or typing in the wrong URL. Having a custom 404 page30 that kindly guides users back to a working page on your site can greatly improve a user's experience. Your 404 page should probably have a link back to your root page and could also provide links to popular or related content on your site. You can use Google Search Console to find the sources of URLs causing "not found" errors31.

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.

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: “What makes a page spammy?: “Hidden text or links – may be exposed by selecting all page text and scrolling to the bottom (all text is highlighted), disabling CSS/Javascript, or viewing source code. Sneaky redirects – redirecting through several URLs, rotating destination domains cloaking with JavaScript redirects and 100% frame. Keyword stuffing – no percentage or keyword density given; this is up to the rater. PPC ads that only serve to make money, not help users. Copied/scraped content and PPC ads. Feeds with PPC ads. Doorway pages – multiple landing pages that all direct user to the same destination. Templates and other computer-generated pages mass-produced, marked by copied content and/or slight keyword variations. Copied message boards with no other page content. Fake search pages with PPC ads. Fake blogs with PPC ads, identified by copied/scraped or nonsensical spun content. Thin affiliate sites that only exist to make money, identified by checkout on a different domain, image properties showing origination at another URL, lack of original content, different WhoIs registrants of the two domains in question. Pure PPC pages with little to no content. Parked domains” Miranda Miller, SEW, 2011
Inclusion in Google's search results is free and easy; you don't even need to submit your site to Google. Google is a fully automated search engine that uses web crawlers to explore the web constantly, looking for sites to add to our index. In fact, the vast majority of sites listed in our results aren't manually submitted for inclusion, but found and added automatically when we crawl the web. Learn how Google discovers, crawls, and serves web pages.3
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 Google Search Console if you sign up.

to avoid throwing link equity away, you might create HIGH-LEVEL IN-DEPTH TOPIC PAGES on your site and redirect (or use canonical redirects) any related expired content that HAVE INCOMING BACKLINKS, to this topic page (and keep it updated, folding content from old pages, where relevant and there is traffic opportunity, to create TOPIC pages that are focused on the customer e.g. information pages)

Advertising with Google won't have any effect on your site's presence in our search results. Google never accepts money to include or rank sites in our search results, and it costs nothing to appear in our organic search results. Free resources such as Search Console, the official Webmaster Central blog, and our discussion forum can provide you with a great deal of information about how to optimize your site for organic search.