The basics of GOOD SEO hasn’t changed for years – though effectiveness of particular elements has certainly narrowed or changed in type of usefulness – you should still be focusing on building a simple site using VERY simple SEO best practices – don’t sweat the small stuff, while all-the-time paying attention to the important stuff – add plenty of unique PAGE TITLES and plenty of new ORIGINAL CONTENT. Understand how Google SEES your website. CRAWL it, like Google does, with (for example) Screaming Frog SEO spider, and fix malformed links or things that result in server errors (500), broken links (400+) and unnecessary redirects (300+). Each page you want in Google should serve a 200 OK header message.
QUOTE: “When our quality algorithms go to your website, and they see that there’s some good content here on this page, but there’s some really bad or kind of low quality content on the bottom part of the page, then we kind of have to make a judgment call on these pages themselves and say, well, some good, some bad. Is this overwhelmingly bad? Is this overwhelmingly good? Where do we draw the line?” John Mueller, Google 2016
QUOTE: “… it also includes things like the comments, includes the things like the unique and original content that you’re putting out on your site that is being added through user-generated content, all of that as well. So while I don’t really know exactly what our algorithms are looking at specifically with regards to your website, it’s something where sometimes you go through the articles and say well there is some useful information in this article that you’re sharing here, but there’s just lots of other stuff happening on the bottom of these blog posts. When our algorithms look at these pages, in an aggregated way across the whole page, then that’s something where they might say well, this is a lot of content that is unique to this page, but it’s not really high quality content that we want to promote in a very visible way. That’s something where I could imagine that maybe there’s something you could do, otherwise it’s really tricky I guess to look at specific changes you can do when it comes to our quality algorithms.” John Mueller, Google 2016
QUOTE: “Many websites are eager to tell users how great they are. Some webmasters have read these rating guidelines and write “reviews” on various review websites. But for Page Quality rating, you must also look for outside, independent reputation information about the website. When the website says one thing about itself, but reputable external sources disagree with what the website says, trust the external sources. ” Google Search Quality Evaluator Guidelines 2019
One common scam is the creation of "shadow" domains that funnel users to a site by using deceptive redirects. These shadow domains often will be owned by the SEO who claims to be working on a client's behalf. However, if the relationship sours, the SEO may point the domain to a different site, or even to a competitor's domain. If that happens, the client has paid to develop a competing site owned entirely by the SEO.