SEO (Search Engine Optimization) is based on the keyword position on search engine, but the ranking for target keywords isn’t simple or direct.
Until 2013 the writers thought it was enough to type the keyword many times to climb to the first Google result, but with the Hummingbird update things are still complicated.
Google has started to look more in the context of all written content and not just words and sentences literally.
The main goal should be to produce the best quality content possible and to write in a way that is informative and natural.