Leading email service providers like Gmail and Yahoo allow marketers to say a little more to their users beyond the subject line, before they even open their email. Consider it a bonus chance to reel in that elusive open, click or conversion!Where once marketers had to depend on custom code to include pre-header text in their emails, that process has now become incredibly simple with the slew of marketing automation platforms out there. Most have WYSIWYG interfaces where you can type pre-header text into a form field, and voila, the pre-header text is set!Things to keep in mind when optimizing your pre-header text:Think of pre-header text as your second subject line. Spend equal thought in crafting and perfecting it.Unlike subject lines, in many cases, the pre-header text will not be cut off and full sentences are often visible, depending on the device being used to view it. Don’t skimp on the length in favor of brevity on this one.Adding a call to action that builds on the introduction offered in your subject line is a great way to improve open rates.Last but most important, don’t miss out on adding pre-header text to all your emails.