HTML emails…. can take a lot of time. Making them work on mobile takes even more time and testing. Here I list things that I found helpful when making emails.
When using Litmus to test emails, I turn off these mobile clients because they don’t support media queries:
Gmail App (Android), BlackBerry OS, Windows 8 Phone.
I haven’t personally used this technique yet but before reading this, I didn’t know it was possible to stack a right column on top in email
If you really need to use background images, this is your best bet (restrictions apply):