I'd like to help out a site that is over 8 years old and ranked in the top 5 for good keywords a couple of years back. It's now ranking in the top 50 as it has been passed up by sites that are updated using white, gray, and black hat techniques. I don't want to try any risky techniques for short term improvements so what can help an established site move itself back up in the rankings? I believe they would buy directory listings in addition to Yahoo! and have resources for PR and article writing. They already spend a good chunk on Adwords and other media.
Build backlinks, exchange or linkbait relative sites with yours and in no time you could be back. What niche is your site? I might have a exchange for you! Oh also, do directory submissions, they help a ton!
still more powerful is the content... ;-) and as long as you follow google guidelines you won't get any problem...
Stay away from any link schemes especially free directory submissions or link exchanges both of which Google has placed in its cross hairs. Next you need to determine if organic listings would drive traffic that will earn the website revenues. Once you know the answer to that question then you can determine where the target market is to be found and then determine the appropriate course of action. If after that you need to use SEO try one way anchor text links and generate some new content for existing pages add a sitemap page, add an xml sitemap to Google & Yahoo to ensure quicker indexing. Peace!