Emails should be 600-800 pixels maximum width. This will make them behave better within the preview-pane size provided by many clients. Design for simplicity. Use grid-based layers and avoid complicated elements that require HTML floats or positioning. Assume images will be initially blocked by email clients, or that certain images—background images, for example—will completely fail to load. Don’t design an email that’s essentially one large, sliced-up image. While these kinds of emails look pretty, they perform poorly. Use basic, cross-platform fonts such as Arial, Verdana, Georgia, and Times New Roman. Avoid elements that require Flash or JavaScript. If you need motion in an email, a .gif is your best bet. Don’t forget about the mobile experience! Is your email readable at arm’s length on a small screen? Will the images slow its load time on a mobile device? Are your links easy to press with a thumb? Best Practices: Development

Much like with design, there are best practices to follow when coding HTML email. Code all structure using the table element. For more complicated layouts, you should nest tables to build complex structures. Use element attributes (such as cellpadding, valign, and width) to set table dimensions. This forces a box-model structure. Keep your CSS simple. Avoid compound style declarations (IE: “font:#000 12px Arial, Helvetica, sans-serif;”), shorthand code (IE: #000 instead of #000000), CSS layout properties (IE: slot, position, clear, visibility, etc.), complex selectors (IE: descendant, child or sibling selectors, and pseudo-elements) Inline all CSS before sending. (MailChimp will do this for you automatically.) Use only absolute links for images, and host those images on a reliable server. (MailChimp provides free image hosting.) Don’t bother with JavaScript or Flash—those technologies are largely unsupported by email clients. Account for mobile-friendliness, if possible. Use media queries to increase text sizes on small screens, provide thumb-sized (~46x46px) hit areas for links. Make an email responsive if the design allows for it. Test, test, test. Create email accounts across various services, and send emails to yourself. Do this in conjunction with services such as Litmus.