SEO is mostly about fundamentals and small optimizations. Loopholes in ranking algorithms are increasingly short-lived and punishable so not worth chasing. The formula is pretty simple:

1. Create high-quality (worth linking to) content/services that are unique.
2. Publish that content with keyword-relevant permanent URLs and well-structured HTML/semantics so the content can be understood/mapped by search engines.
3. Accrue authority/rank by being the most linked to resource on a given subject (caveat: from sources with worthy authority/rank).

Optimizations come in the form of tailoring content for the specific language of your users to aid discoverability, but the golden rule is create good content for users (not for robots) because the algorithm can tell the difference.

That’s organic SEO in a nutshell. It’s hard to produce good original content and growing rank takes time. It’s the necessary long tail strategy.

SEM

The other side is SEM (search engine marketing) for paid placement in specifically targeted keywords. Any site can participate by paying, but SEM is extremely competitive and in many cases not a surefire profit center that it used to be. The highest keyword bids are not the final straw anymore, and organic SEO rank plays a role in SEM.

Ultimately Google wants to show ads users will click not because they get paid, but because it solves their problem and will endear them to continue using Google. It’s not as easy to buy your way into a market anymore with SEM alone.

SEO & SEM on the home page

Relative to the home page, content decisions purely for boosting organic SEO will have a small impact. It’s much more important to drive the genuine business objects and let the SEO fundamentals take care of themselves.

SEM relative to the home page is more connected. If you’re paying to drive traffic generally for the business (not a specific keyword / landing page), then the content users see on the home page should reflect your SEM campaign to be relevant.