10 essential email design tips from Justine Jordan http://content.myemma.com/h/i/268624866-10-essential-email-design-tips-from-justine-jordan
The 6 Best Practices for Responsive HTML Email Design https://mailbakery.com/blog/the-6-best-practices-for-responsive-html-email-design/
How to Use the Right Images in Your Email Design http://blogs.constantcontact.com/use-images-in-email-design/
A crash course in the essentials of email design, coding and data http://www.exacttarget.com/products/email-marketing/email-design-toolkit
The Finer Points of Styled Alt Tags http://blog.goolara.com/2013/01/24/the-finer-points-of-styled-alt-tags/