On-page SEO is no longer a simple matter of checking things off a list. There's more complexity to this process in 2016 than ever before, and the idea of "optimization" both includes and builds upon traditional page elements. MOZ has written an amazing article that walks us through what we should be focussing on for effective search engine optimization.
https://moz.com/blog/on-page-seo-8-principles-whiteboard-friday
