A WebmasterWorld thread has two moderators offering some basic tips on how to garner more links for your web site.
The easiest method is to find links you already have but might not be counting.
Buckworks from the forum suggested using Google Webmaster Tools, going to the "Not Found" report in crawl errors and making sure to 301 redirect those URLs to the relevant URLs that currently exist on your site.
Yes, this is a basic SEO tip, not just for link building but for overall good SEO practice. We know it only takes a couple weeks for a 301 to pass the link juice from the old URL to the new. But we also know there is a minor dampening factor for 301ed link juice.
The moderator of the WebmasterWorld link building forum, martinibuster, also suggested that you look for links to pages that don't really link anywhere. Pages such like PDF files, Word documents, and other non-HTML pages and suggest the linker link to the HTML page instead.
There are tons of tips like this, so make sure to join the thread and chime in.
Forum discussion at WebmasterWorld.