When writing a post, have your site opened in another tab or window. Open the category from your sidebar that you plan to put the current post in and you should instantly have some archived posts on a similar topic to work in a few backlinks. Same idea applies when going back to update older posts.

One final trick, pay close attention to your web logs and make linking forward a priority on older posts that are doing well in search engines. This way, new readers from search engines are more likely to click-thru and find more current content. If you are like me, my content tends to get better the more I write, so hopefully this will impress a few visitors who will stick around as subscribers.