Older SEO information will tell you to choose a main keyword phrase and aim for a specific keyword density. Unfortunately, Google and other search engines have changed their algorithms and ranking strategies and this strategy no longer works well. Instead, you want to write on a topic instead of just keywords.
You should still choose a main keyword (phrase) and include it in the title and a few times in the content. Then, using your main keyword (phrase), you need to come up with five to seven related keyword phrases to build your topic. If the main keyword phrase you want to target is “Business consulting” you might also use related keyword phrases like: