Easy to find call to action
Include a single, prominent and appealing, primary call to action so your readers know exactly what you want them to do. If you are including social sharing buttons, remember each is a call to action as well. So, make sure your primary call to action is more prominent than the rest. If you do include a navigation bar, ensure it doesn’t take away people’s attention from the primary CTA.
Don’t hide your CTA in an image
Don’t stuff your emails with too many
Use a HTML based button for your primary call to action instead of plain links or graphic buttons
Place your call to action at the very top of the email, so that your readers don’t have to scroll through a lengthy email to get to it