if your site and another are about equal in content value, the site that's been more recently updated will appear higher in the search results. So now it's no longer sufficient to have great, well-structured content. That content needs to be fresh as well. So here's your assignment:
- Look at your Google Analytics and see what key words people are searching for when they find you.
- Look at your site in the administrator side and see what articles relate to those terms.
- See when you last updated those articles.
- If it's been a few months, see if there's anything new you can add to the article.
- Set yourself a regular schedule (weekly, monthly, quarterly) to update content.
The alternative is to start slipping in the search rankings.