Having been at it for over 15 years, something I know a fair bit about is SEO or what I now prefer to call optimized content marketing. I do not like the terms expert or guru, but I believe I have a good handle on the best practices required to improve online visibility, which I will provide a short simplified summary of here.
While SEO has evolved over the years as Google builds more smarts into its algorithm, basic principles remain the same. In short, you need to convince Google your content provides the best answers to the questions people are searching on. You content deserves to be #1. The two primary characteristics of successfully optimized content are relevance and authority.
If you have existing content i.e. a website, a blog, YouTube videos, etc. the first step is determining whether or not any of your content has any authority or momentum in the eyes of Google. Is your content currently being found and if so, for which keywords? Keywords are still very important. The focus should be on incorporating groups those keywords and phrases into content which addresses the intent of your desired audience i.e. answers their questions. This is where traditional technical SEO comes in as those keywords must be used in the correct places such as Title tags, Heading tags, ALT tags on images and meta descriptions. Here Google is still a machine and rigorous structure matters.
But it's not enough to simply stuff keywords into structured content. Rather, your content must be something your audience wants to read or watch, like and share. Key to this is content which is accessible, particularly on a mobile device as this is where a growing majority of searches are being performed.
Assuming your content is easily consumable and relevant to your audience, liking and sharing will lead to others potentially liking and sharing or thereby creating backlinks, which sends signals to Google regarding the content's authority. Backlinks are all about your content being found in other relevant places. Pro Tip: If you are hunting for backlink sources, look no further than the search result pages themselves for the keywords you want to be found for. Any non-competitive sites in the search results are by definition your most relevant potential sources.
If you are starting from scratch all the same rules apply and depending on the audience along with the quality of your content it will simply take longer to build your authority. Optimized content marketing to increase your visibility is an unending marathon, not a sprint. The long term payoff is a targeted, highly engaged audience who want to buy whatever you're selling.