Someone recently sent me an HTML email that did pretty much everything wrong and I had to redo it from scratch. He asked me for some tips for creating the next one and I sent him a quick list off the top of my head. I’d be interested in knowing what others think of this list and if I forgot or misstated anything.
* Don’t rely on any code in the document head or body tag; all styles must be inline (including link colors, etc.)
* Avoid background images (since they are often removed when the recipient views the email), or if you use them make sure they contain no important content (logos, etc. should always be inline images)
* Always view your design without any images and make sure that it works that way; avoid text in images, and always use ALT tags for images with important content (images with no ALT tags can also get your email flagged as spam, since many spammers send messages like this)
* All URLs and IMG paths must be complete (not relative)
* Keep your code as simple as possible (old school table designs work better in emails than XHTML) and always view and optimize your code (you can’t just use the WYSIWYG visual editor in a program like Dreamweaver - that makes for messy and unreliable code)
* Keep the file size and number of linked images as low as possible (compress images properly and remove their meta information)