"Ensure the content in the body of the email is well-branded, contains relevant content and has clear and compelling call-to-action links that are evident early on in the email-above the fold," Turnbull says. "These important links should always be tracked, so those [who] click through (or not) can be potentially targeted in the future."

Research Manager Aliya Zaidi says email is no longer just on a computer-it's also mobile content on smartphones and . As a result, Zaidi's email marketing tips include being aware of how your message is delivered and displayed on different mobile devices. "Think about touchscreens and how you can optimize an email to improve this part of the customer experience," Zaidi says. For some, mobile is read offline, which limits real-time offers in the content, she says. On the other hand, mobile does let you do some things better, such as target by location.