A Couple Of Fundamentals
Google aims at "serving the best content as fast as possible to user requests", said Amith Singhal. Contrary to its main competitor (Microsoft Bing), Google drives most of its revenues from its advertising business. Without it, it dies.
Google has real people reviewing websites and search results in order to create mathematical models. It does not try to guess what will please users out of thin air. These models are reviewed frequently, and are used to analyze all websites. Their metrics are help producing rankings in search results.
Therefore, trying to please Google algorithms without satisfying users in the first place is one of the biggest mistake still made by many. This does not help Google meet its business constraints. Google's business model needs satisfied users.
Also, there is a thumb rule in finance: "Don't fight the Fed!". It means that whatever financial strategy you decide to implement, it should not go against the Federal Reserve's decisions and rules, or you will fail. The Fed is stronger than you. In SEO, it's "Don't fight Google!". Fail to comply with their rules and guidance and your will fail your SEO for sure.
So, what do you need to keep in mind?
Accessibility, Trust, Relevancy & User Experience (ATRUx)
2. To serve quality results, Google needs to trust that content first. It's not because I claim I am a dentist on the Internet that I am one. Trust is mainly established through links coming from authoritative (and relevant) websites. Authoritative websites are those having many trusted links. Unnatural links don't count and can lead to ranking penalties.
3. In order to match user queries with content, Google must establish the intent of the query and the content's relevancy. Google bots are not good at guessing and reading between the lines. You need to include the keywords (or synonyms) you are aiming for naturally in your page. It is necessary in order to rank in search results.
4. At last, Google must confirm that its users are satisfied, that they had a positive experience from using its services. There is no abstract quality metric for content, but Google assigns quality weight and trust to sites. If they can't confirm satisfaction after exposing your content, it will stop ranking on the long run for sure.
ATRUx is the acronym summarizing what you need to remember regarding SEO strategy. It's the set of rules used by the 'Fed' in SEO. Fail to remember these driving factors and you will fail your SEO strategy implementation for sure.
Competitive vs Non-Competitive Niches
If you are in a non-competitive niche, then your primary focus should be to create content which satisfies user queries in order to obtain traffic. It is more important than building backlinks.
If you are in a competitive niche, serving the same (or equivalent) content as other website is useless, especially when you have less authority than them. To beat competition, you need to build up your authority or at least to deliver original and useful content. Does it bring value? Remove or deindex low quality content on your website. Quantity does not matter, quality does.
If you are in a e-commerce competitive niche, you will most probably have to use advertising to appear on the first page. It will provide better returns than traditional SEO tactics.
Thinking Out Of The Box
Being ranked at Google should not be your only obsession. It is not the only source of traffic. You can acquire a lot of traffic from social medias too. Therefore, make your content shareable with social buttons.
Keep in mind that, ultimately, ranking is about having more traffic. It is a mean, not the objective!