On-page SEO is not magic — it is a handful of fundamentals done consistently. Get these right on a new site and you give every page a fair shot at ranking.
Start with structure
One clear H1 per page, a logical heading hierarchy, descriptive title tags and meta descriptions, and clean, readable URLs. Add descriptive alt text to images and make sure internal links point where they should.
Then make it fast and mobile-friendly, because performance is now part of how you are judged. None of this replaces good content — it just makes sure the good content can be found.