Cutting your teeth in email design requires knowing the quirks of the major email clients. If you or a team member has just been introduced to the black art of email design, these simple tips may just save you hours figuring out why your design looks broken on certain major email clients.
Update: You can skip #4 as Yahoo! Mail fixed their media query bug in 2015
Download 6 Email Client Hacks You Need To Know.
For a detailed breakdown of the CSS support of the major email clients, check out Campaign Monitor’s CSS Guide.