This my seem like an unusual source but I found it to be right on the money. It is only one page and will take you all of 5 minutes. I found (or had forgotten) several pearls and here they are
1. Are you submitting your site to to DMOZ.org
http://www.dmoz.org/help/submit.html
2. when was the last time you updated your site map?
http://www.xml-sitemaps.com
3. Are you photos tagged? Use the ALT tag to identify what is on that page.
4. Make each page of your web site have a unique title.
5. Is someone on your staff working the forums for your industry and local market to place questions and ideas about what "the market" should be thinking about so that you become viewed as an expert? Are the links coming back to the right landing page?
6. Have you run your site through Google's URL evaluator to see how your site is searched?
Read more here
http://www.costcoconnection.com/connection/201102/u1=issues?pg=28#pg28
Source: The Costco Connection Article by Andy Tilbrook