Content is king, it is everything! Though it still has other criterion for SEO, without content, it's nothing. What I am going to emphasize is that you must concentrate more on your content. Of course, url and heading are helpful when it comes to SEO. But, don't forget, links, urls of your site are just occupying a small little part of your site. In majority, contents take up more than half of a site/blog.
Well, search engines made a big deed——classifying billions of sites accordingly to the certain keywords. Sarcastically, why do some of uninformative sites will be placed on top of the better site? It sometimes related to contents. Of course, a site which provides great informative articles is considered as a great site, but eventually, they fail to optimize keywords, and keywords-stuffed contents will seem to be gross and odd. Why? There are many reasons——backlinks, contents... But, for now, I'm going to say about contents first.
The bad and uninformative site can win over a great informative site, as they got their keywords optimized. A great site should concern of this big problem. Instead of just posting a great articles, try to place some keywords into the contents, until the optimum keyword density.