Here are some rules that may help you. These are generalized and there are always exceptions to rules in life, but overall I try to stick to these principles:
Only use one H1 per page.
Properly nest your H2 and H3 content.
Use category or main pages to index your own articles, services, products, etc.
Use "detail pages" that have proper URL slugs for individual pages inside /blog/, /services/, /products/, etc such as /tutorials/seo-longtail-keywords.html
Every image must have an alt tag, and should use lazyloading to help with speed & performance.
Your pages should have
valid schema
Use meta content for your title and description mostly. Keywords can be helpful but is not as important as actual site content.
Don't overuse keywords in your content.
Write unique content that a real human will actually want to keep reading. This part is very, very important.
Research your competitors, target audience, and the most current news for your industry niches.