The following practices should be considered when designing emails that you intend to send to smartphones or mobile devices.
Watch your email width
In order to ensure that the email is not too wide to be easily viewable on the screen, the width of the email should not exceed 600 px (by default, the ClickDimensions email template block editor has a width of 600 px). Making the email too wide will cause the viewer to have to constantly move the email back and forth as they read it in order to be able to see all of the content. This is frustrating and may deter recipients from reading your emails.
Cut down on the size and number of images used
Images should generally be smaller than those used in a standard email because smartphones and mobile devices will generally not be able to download the images as quickly as a desktop would. Smartphone and mobile device contracts also generally include limited data allowances, so larger images will eat up a larger percentage of the recipients allotted data. Including Flash or gif animations in your email should also be avoided because they will further increase the file size of the email and some smartphones and mobile devices do not support Flash. Taking these factors into account will help improve email deliverability since images with a high image-to-text ratio are more likely to be considered spam (a 60:40 text-to-image ratio is generally considered to be fine).
Include a text version
Include a text version of your email in case the recipient's device has difficulty processing HTML.
Provide Links to extra content
In order to cut down on the length and file size of mobile emails, provide links in the email to any content that is accessible in another location, such as your website, and is not essential to the purpose of the email.
Use a Simple Email Layout
In order to increase legibility and make efficient use of space, use a simpler layout for mobile emails. Mobile emails often use only one column and incorporate larger links and buttons in order to allow for greater ease of use with touch screens.
Use brief and direct email subjects
Since smartphone screens have a limited width, your email's subject should be brief and to-the-point in order to avoid having it truncated to fit the screen.
Use Web Safe Fonts
Web safe fonts are fonts that are recognized by all email clients. It is recommended that you use one of these fonts for your email because if you do not, there is a possibility that the font will not display correctly on some email clients. If the font is not recognized, a web safe font will replace it. If you want to use a non-web safe font, you can specify in the email's HTML which web safe font should be used to replace it if need be. All of the fonts available in the ClickDimensions email template editors are web safe fonts.