The ironic thing is the question itself leads you down the wrong path.
The question implies what is most important about being found through Internet search is SEO.
While SEO is a critical component of being found (very critical in fact) a fairly small static website where all the SEO aspects are done extremely well will not get your website found.
In general (and there are some exceptions to this rule) websites that rank high are website that publishing a steady stream of fresh content.
So the single best piece of SEO advise is to publish more, but ensure that your website overall, and everything you publish, is properly formatted for strong SEO.
The key concept here being Inbound Marketing (the larger picture of what people do when they do SEO) looks very much like journalism overlaid with a marketing intention.
Along those lines, the best advise is to:
- Know who you’re working to attract.
- Know the process of how they buy what you’re selling (the procedure they go through).
- Create some gated content they will exchange their name and email address for.
- Publish a lot of content that is interesting and useful to your target audience.
- Do not stay exclusively on your topic or product.
- Implement the first step or two of your sales funnel through well placed Calls to Action at the bottom of every blog post.
- Once you have their contact information nurture the leads via email marketing and/or marketing automation.
It is a tried and true formula and it works.SEO Needs Link Building