Buying incoming links:
Although this is a quick way to generate backlinks, buying links from high ranking google websites or “link farms” is seriously looked down upon by Google. Google is more intelligent than most people think and knows when a link is artificial or has been brought on a high ranking site for the sole purpose of increasing backlinks. Although sites such as Forbes and Entreprenur are highly ranked there is a thought process in 2019 that Google knows people buy links from these types of sites and will turn down the “weight” in the boost that these types of websites deliver.

Spamming:
Search bots know when a comment is spam or is not comprehensible by humans. This includes spamming comments on blogs or writing crazy blog posts through your content management system with random sentences and keywords in linking back to your site, search engines can pick up on this and they will penalise your search engine rankings.

Over using keywords:
Adding more keywords does not improve your SEO search rankings and can also do your rankings more harm than good. You keyword should be used no more than 3% in your entire page, so use it once or twice for every 100 words you write.

Unrelated Linking:
Your backlinks should all be from relevant websites, so if you run a website that Is related to formula 1 for example and have a back link from a palm reading website, they have no relation and the back link will not count for much.

Poor Website Development
In 2019, Google loves and we mean LOVES user experience, which at the foundation comes down to a well-developed website. Whether that be from a UX or programming point of view, your website development should be second to none.
When choosing your website development company have a sit-down meeting with them and discuss SEO – Ask them what framework your website will be built on as platforms such as WordPress give an SEO boost. Ask them about load times and content delivery networks and how the way your new website is developed will affect page speed and SEO.