For content to appear in the search results it needs to be relevant to the keywords searched. If somebody is search for surfboards in Iowa, the keywords surfboards in Iowa should obviously be in the content.
Matt Cutts says the most valuable real estate in a blog post is the subject line. Keywords should be in the subject line / title of the post. If it is a webpage, keywords should be in the page title and meta description.
Keywords should also be sprinkled throughout the content in a natural way. It helps to emphasize keywords in bold or header tags when appropriate.
After Google determines that content is relevant to the search query it has to judge the quality of the content.
In the past Page Rank was a very useful indicator of quality content. Page rank is based primarily on inbound links. Google assumes that if quality websites are linking to content on other websites the content is good.
However, now Google is factoring in social signals. If people comment on a blog post or share it on Social platforms like G+ and Facebook, where it gets more shares, likes, plus ones, and comments it is another vote of confidence.
Author Rank / Reputation Score
Although some SEO pundits deny that Google is scoring writers and using this as a ranking factor, more and more experts are seeing the light and acknowledging this possibility. If an author has a body of work demonstrating his expertise that receive positive social signals, than the reputation score of the author can be a factor in influencing the ranking of content. This is similar to page rank in providing Google a vote of confidence about the value and quality of the content.
Relevance and Reputation
It takes both relevance and reputation to get content to appear at the top of the search results. The content has to be relevant to the search query first. This is being ignored as many SEO pundits declare just create good content. It can be the best content in the world but if it doesn’t effectively use keyword so that Google knows the content is relevant to the search query that content will have a tough time achieving top rankings.