Content, is the greatest factor, but there has to be someone linking to it, the most important idea is not much good unless its knkown about
goto the google webmaster tools page
read & follow the instructions
Google appear to have a pretty good idea, about what search engines expect,, :P
avoid all promises of instant results, doesnt work
Although a good quality content place an important role in google ranking but this doesn't meant that it is the only one that can bring your site and ranking to a great height. There are lots of other things that do matter for this. You may read some blogs or articles on this which defines the factors affecting Google Page Rank.
Content is the king to increase ranking and traffic if it has relevancy according to keywords, there is no doubt, but we increase its link popularity that work like booster and helps to increase ranking and traffic with in short time,
Good quality content certainly play a vital role in bringing your website to top ranking but you can;t say that it is the only thing.There are lot of factors involved. In SEO there is no concept of choosing one thing and relying on it completely. hope it will make sense to you.