With more emails being opened on mobile, not only should they be formatted for smaller screens, but messaging needs to be to the point and action-oriented.

The key to success is not just making a message fully viewable, but ensuring the most important content elements are easily accessible and actionable.

?When creating email with mobile users in mind, designers should think in terms of lists and easily scanned information, not prose and essay,? said Tom Schneider, associate partner and group experience director at Rosetta, Princeton, NJ.

"These are not the written letters of days gone by,? Mr. Schneider said. ?In the mobile context, these are quick three to four second distractions that are either immediately meaningful or gone in a tap.?

Call to action 

Email rates on mobile devices continue to climb although smartphone growth is at a slower pace than tablets, according to new data from Knotice.

In a study of retailers? emails opened on mobile, Knotice found smartphones lead during most of the day, except from 6 p.m. to 11 p.m. when tablet use dominates.

Among its mobile best practices, Rosetta recommends using email-safe fonts such as Tahoma or Times New Roman which work well on all devices, and not to rely on imagery. The latter is important because not all devices display images by default.

The call-to-action should dominate the design and alleviate the need to scroll. Rosetta also advises to use a grid system with vertically and horizontally aligned blocks to keep HTML fluid.

When sizing, Apple suggests using font sizes of 17-22 pixels and headlines of 44 pixels tall in order to render appropriately. Designers should keep common mobile screen aspect ratios in mind and scale to 320 to 550 pixels wide.

Functionality testing 

To reach smartphone users effectively, marketers might also offer a link to directions or a click-to-call phone number at the top.

?You have to look at the context of the person viewing the email and what is the information they really need,? said Patti Renner, marketing manager at Knotice, an IgnitionOne company, Akron, OH.

?Make sure you are not asking too much of the viewer,? she said. ?There is nothing more infuriating if you want to call the store and you have to scan for what should be really obvious.?

Renner said designers should take a customer-focused view when testing for functionality.

?Each part and each click should take them easily along the journey to conversion or whatever the goal is,? Ms. Renner said.

Another tip to encourage open rates is to use a person from the company as the sender, to make the email more personal.

Responsive design

Matthew Caldwell, vice president of creative and agency services at Yesmail, Portland, OR, said the firm has taken a dual prong approach in designing email for a variety of devices - scalability and use of responsive media technology.

?Scalability means it is an easily pumped up layout,? Mr. Caldwell said. ?That means bigger type, bigger buttons and bigger white space ? and you are keeping the overall email at 600 pixels wide or less.?

Yesmail Coca-Cola design

An email is scalable if 100 percent of the words can be read and buttons can be clicked when opened. Through responsive media an email is automatically modified to the screen on which it is opened.

Yesmail also sees a huge benefit in building an email blueprint for clients.

?What we preach is the importance of templates,? Mr. Caldwell said. ?You will have different modules or sections that can be modified for each new email, rather than re-design and Photoshop every time.?

The template system enables the creation of messages right in HTML code, reducing the time to publish. Part of that is having a standardized header and foot, something Yesmail calls the ?hamburger bun.?

Yesmail has used responsive design and its flexible template strategy successfully for clients Marriott, Domino?s and Duluth Trading, among numerous others.

?Try not to waste users? time if you really don?t have anything meaningful to say,? Rosetta?s Mr. Schneider said. ?It won?t take many irrelevant messages for a user to determine that a brand is just broadcasting noise,?

?You don?t want your brand put in that category,? he said. ?That?s a quick route to the spam folder and it?s a tough climb out once you?re in there.?

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