I think if you are looking entirely just to rank you will have to look at the competition in the space. Be sure to consider quality of the content just as much, if not more, than the quantity of the content.
Additionally, you should be focusing on creating content that serves your target audience. Can you produce enough valuable content to serve the market as an authority? Or, will people find your site and go elsewhere to find what they are looking for?
You should also focus on creating your content for multiple readership paths, i.e. - headings, subheadings, images, and links. Not only does this provide value to your audience, but will help in your rankings as well, contributing again to the quality rather than the necessary quantity.