Rand Fishkin says that gaining new links for old pages starts with updating old blog content with new information. Linkbait doesn't have to go on new pages. It can function well on old pages, too, he writes. Fishkin lists four strategies that can help you refresh content and build links, including running an annual contest to repeatedly garner links to the URL, or update posts with current information.
While some believe blogs should remain untouched once posted, others such as Fishkin think posts do well as updates, too. Fishkin also provides information on troubleshooting pages you submit to major social marketing services. The guidance should help you keep old pages with new content ranking higher in search engine queries.