Writing an article for the general users is easy but to write for both the users and as well for the Search Engines is tricky. Over the years I have found out many people asking me this question on how to write an article optimized for the Search Engines as well for the rationale visitors.
The answer for the question is simple write for the visitor and make sure the article includes the keywords based on your research at a pre defined keyword density. Keyword Density generally means the number of times the keyword occurs for the full article. Suppose a particular keyword occurs 10 times in an article having 500 words then the keyword density stands as
(10/500)*100 = 2%
You need to understand what is the best keyword density as per the theme of the article and also the length of the article?
Regarding the best way to insert the keywords, there are many authors who believe there are many ways of distributing the keywords and even some say that you should maintain a z structure or a v structure. According to my knowledge and over the years of experience what I have gathered is straight and simple.
You need to insert the keyword and also synonyms of the keywords in each section that is the Introduction, body and the conclusion.
Google along with other search engines have laid down their own algorithm but each of them have some thing in common and that is the article should be well structured without grammatical mistakes. This is because it makes much sense to the visitors and that is what every search engine asks for.
Make sure that your article is not over optimized due to the influence of the keyword as that will hamper your growth more than it will do good for you.