The only way to build relevance for your website is to publish more content. Creating an effective content plan is about mapping your website's overall topical relevance and identifying content gaps.
Content Gaps
You and your competitors are all talking about the same industry and services. Even if you feel the information in your field is abundantly available across the web, it still needs to be abundantly available on your website. Cover all the topics your top competitors have covered, then cover some more.
Distributing Relevance
Having tons of published content is a fantastic step in the right direction. It will do wonders for increasing your entire site's relevance for whatever it is you're talking about. When you start to connect all your topics together, you can push even more relevance through your entire site. This is a strategy called internal linking and it is the rockstar of on-page optimization.
Putting It All Together
Once you've identified where your content gaps are, you can create an effective strategy for addressing common topics and questions your customers may have. You will also also improving your site's relevance and introducing internal links.