I receive Email Insider, an e-newsletter on email marketing. I found this article interesting and useful. Some of the articles aren't applicable to small and wahm businesses. But this one discusses the use of text vs images in newsletters. The other interesting point is including in the Subject Line the "bottom line" or discount code so potential customers don't even have to read the newsletter to get the point.
With the amount of email folks will be getting the competition for sales this holiday, I plan on using this advice in promos for Comfy Cozy Glow in the Dark pillowcases.
Chad White is the Research Director at Smith-Harmon, an agency focused exclusively on providing email marketing strategy and creative services. Visit his blog at http://www.retailemailblog.com/