Using a ladder system allows emails to scale down much more neatly. You want to avoid using tables or setting image size widths, in order to ensure that the email is "elastic" and adjusts to the size of the mobile screen. You'll also want to group multiple items, links and images on top of each other (like a ladder). You can then use background colors within the email itself to serve as dividers between the different sections. This stacking system allows for easy organization and alignment with limited rendering snafus. The goal is to lead your reader down the email, through the content.
4. Padding for Fingers in Motion: Point and click motions are fluid and precise when done on a computer mouse connected to a desktop or laptop; whereas, mobile devices use touchscreen technology and the bulky human finger becomes a factor. Email designers need to anticipate how fingers will navigate the clickable areas of an email on a touch screen. This means buttons and icons need to get a little larger and the surrounding areas need to be more padded to accommodate for fingertips in motion.
Allow for 10 pixels (give or take) around or in between any clickable area to leave space and make it easy for users to navigate and click to take action. Also, allow for about 20 pixels to 30 pixels around the border of the email for fingers to hold the tablet device. You don't want key information hidden under the user's thumb.
5. Font Sizes: Another design tip for clumsy fingers is to use a minimum font size of 12-point for body copy and a maximum headline size around 20 points. Any larger and you risk your email landing in the junk folder for desktop users, because some filters flag larger fonts used in email as spam. Keep in mind that the larger font means you'll have to keep your content brief. You'll most likely be able to fit 10 lines to 12 lines of text on a screen.