How do you make your responsive email work in such conditions? By using dirty little CSS tricks, of course. TutsPlus' series on building their emails features a few of those tricks, while Campaign Monitor suggests mobile-first emails. You can also use templates and patterns and libraries and resources and quite a few HTML email frameworks.
State of email design
Creating HTML Emails
Premailer has several tools for cleaning up your HTML email code
Zurb has a great set of responsive templates and good documentation on using them.
HTML Table generator - very helpful for laying out email newsletters. Also consider reading Creating a Centered, Responsive Design without Media Queries.
Consider switching to all plain text emails.
Optimize Images for Emails on Retina Displays
High-pixel density displays are becoming more and more common, but an increase in pixels per inch can make small images look fuzzy and unfocused. Fabio has a simple way to avoid using ugly images in emails:
Double the size of the image, and then constrain its width with either CSS or the width attribute on the img tag. The result is an image that maintains its sharpness on new device screens and works across many email clients.
This page contains information I gathered and thought were very useful. See more notes on programming.
Just to let you know, this page was last updated Tuesday, Jun 19 18