Another piece of wisdom from TheHoth blog.
In summary, don't think of your articles or blog posts as set in stone and static in time. It is a good idea to re-visit some of your previous blog posts and 'freshen them up a bit'. Revise the content, extend the content further to add new information and change the date so that it become current again (Google loves fresh content).
Also if you can, reference other articles from within your blog posts such as the one on SEO mistakes on the Home page. By internal linking to other posts on your site you are providing links which whilst not as good as links from other sites are beneficial to your SEO.
For more current tips on SEO read this article.