Improve Email Marketing Using Principles of UX Design http://isenselabs.com/posts/how-to-improve-email-marketing-using-principles-of-ux-design
The Anatomy of a Perfect Holiday Greetings Email http://www.rybbon.net/blog/the-anatomy-of-a-perfect-holiday-greetings-email-by-emailmonks/
Typographic Patterns In HTML Email Newsletter Design http://www.smashingmagazine.com/2015/08/typographic-patterns-in-html-newsletter-email-design/
Modern Trends & Design Ideas for Email Newsletters http://marketblog.envato.com/trends/modern-trends-design-ideas-for-email-newsletters/
The Ultimate Guide to Preview Text Support https://litmus.com/blog/the-ultimate-guide-to-preview-text-support
Four Creative Email Experiments You Should Try http://blog.hubspot.com/marketing/email-marketing-experiments