What exactly makes a website good for SEO purposes is its content, which is to be of good quality. If a website has proper quality content added with phrases what people use to search in the Google search box then that website will have a good SEO ranking and with that what I mean is that it will show up on the top search results of Google.
Adding to this, I would say that majority of Internet users basically search for common topics like songs, technology, or education so if content related to these are published on a website then that website would have more chances of reach. However, the quality of the content matters the most for a website to have a good SEO ranking.
I find that the harder I work, the more luck I seem to have.