There's no one set of "correct" keywords.
When you sit down to write an article, the best thing to do is just write it naturally. Then, think about what a person using Google would do to find your article. Ask yourself what they would type in the search bar to find your article or similar pieces. Make a list of those words and phrases and try to include them in your article in a natural way when you go back to edit. Try to include those words in your titles, subtitles, and headings as well.