Search Engine Optimization encompasses both on-page & off-page ranking factors.
Organic search ranking begins on the web page with title tags, headers tags & useful content.
The best practices for organic search engine optimization starts with a well-crafted web page. The web page needs to speak to the needs of a potential customers (i.e. what they are searching for). And, that search intent needs to be crafted into the hidden and visible elements of the web page within the correct length specifications. There are hidden page title tags, meta descriptions and Schema to influence the search ranking, the actual search listing and drive click-throughs. There are on-page header tags to indicate primary and secondary content. Then, there's the content itself, which is becoming the most important on-page ranking factor of all. The content has to be original, authoritative and lengthly.
Search Engine Optmization goes way beyond the web page with hundreds of off-page ranking factors.
Influencing the off-page SEO ranking factors is time consuming. And, the results can be difficult to quantify since it can take the search engines up to a year to rerank the website. It starts with easy fixes like making sure the website has a secure certificate or does it have a high PageSpeed with a fast server and compressed images. Next, there are social signals like does the brand actively post and have mentions on social media channels. Now, it becomes difficult -- "backlinks". How many other third-party websites link back to your website? Backlinks have a high influence on ranking but link building activities are extremely time consuming. While natural, unsolicited backlinks are desirable, that's a lengthy waiting process. Last, but not least, are the more esoteric off-page ranking factors such as website authority, trustworthiness and reputation. Is the content original and in-depth, or does is it copied from other websites? Can the website be trusted or does it have spam content? What is the reputation of the website as mentioned on other review websites or complaint-boards? Each of these, along with dozens of others, needs unique strategies to manage and attack for successful organic search engine optimization.