Opening their e-mail. When focusing on getting the e-mail opened, "from" lines and subject lines are critical. Frequency also is important, though often overlooked. If you e-mail too often, your open rates may drop; e-mail too infrequently and you will miss opportunities to get your message out. So it is important to test frequency to find the balance that maximizes sustainable ROI.
Interacting with the e-mail by clicking through.
Converting on your offers and calls to action. For example, do they complete a purchase, fill out a survey or call a specified phone number?
Notice that each element is usually dependant on the proceeding step. If your e-mails have a low open rate, then the click-through rate will usually suffer as a result.
Additional items to consider when testing include: segmentation, personalization, landing pages, day/time sent, length of copy, intro text content, intro text style, body text content, body text style, closing text content, closing text style, bullets or numbering, view above the fold, images, response buttons, color, coupons/discounts, sense of urgency, pricing, unsubscribe wording, taglines, creative, press mentions, store locations, conversion-online, phone or both-animations, charts, strikeouts, signatures, testimonials, celebrities, polls/surveys, sound, discounts, refer a friend, click to talk.
Establishing discipline around testing is the most critical step. Commit your organization to constant improvement and watch your e-mail effectiveness soar.
Morgan Stewart is director, strategic services, at e-mail service provider ExactTarget (firstname.lastname@example.org). Barry Stamos is chief strategist with e-mail marketing agency INBOX Marketing (email@example.com).