In the searches made on Google, word groups or sentences have started to replace word-based searches. In these circumstances, long-tail keywords became more preferable in articles. 
The keywords used in previous article works caused many unnecessary links to form and directed visitors to the contents full of advertisements. As a result of this situation, Google has put its new algorithm into operation and punished the websites that attract visitors by using this kind of unnecessary words. 

So, how do we find long-tail keywords while we are doing SEO works for our websites? 

The only thing that we know for sure until now is that Google prefers naturality. While creating content, put yourself in the visitors’ position and determine how you will search for what. Accordingly, diversify your keyword groups. If the keyword groups that you have prepared are fully providing the right answers, start creating your content in that direction. 
After preparing your article with all main and sub titles, recheck your article. Check if the unity among the titles continues, if there is ambiguity and if you properly concluded the topic at the end of the article. If you are satisfied with the latest version of the article, you can publish it. If you are able to support your article with visuals, adding accurate images with accurate sub titles will also satisfy your visitors visually.