The content contained in the top line of an email is known as the preheader, and it is an extremely influential factor that can powerfully drive opens, second only to the subject line. Here are the best ways to get the most out of your preheader.

The preheader has to be one of the most woefully misunderstood and underutilized tools in the email marketer’s arsenal. It is most effective when it is used to support the subject line, never in copying it. You might apply the preheader to promote a secondary offer, or count down to a deadline: “Sale Ends Saturday!” Consider the preheader just about as important as the subject line, and dedicate as much time to crafting a perfect one.

Keep your preheader succinct and down to a single line. If you need to explain that should the customer have a problem reading the email there is another version on your website (or formatted for mobile viewing), shorten it to “View Webpage” or “View Mobile Edition”. Whenever including links in a preheader, it is good practice to revert back to 1995 Mozilla convention and underline the text in the link. That underline will clearly indicate to the reader that the content is clickable.

While on the subject of mobile editions, many email marketers are unaware that left-justifying the preheader makes it prominently visible in both the vertical and horizontal preview panes on the tiny mobile screens. Any content that is right justified will primarily appear on larger screens such as tablets or conventional personal computers (remember them?).

A proper preheader will be neither too bold nor overly unobtrusive. It is just as bad a mistake to trumpet your preheader in Screaming Scarlet 36-point Bold Italic as it is to turn it into a crypsis wallflower through a 7-point light font in Dove Gray. The preheader is not so much headline as it is both introduction and summary. Some email marketers have become experts in condensing powerful calls to action to fit into an epigrammatic preheader, and it is a skill well worth developing.

Another oft-repeated mistake is to place the exhortation to share or forward the email in the preheader. It is both presumptuous and ludicrous to expect your customer to make a determination to pass your email along before they have even opened it and read what’s inside!

Even though you may have your coupon code automatically activated via a clickthrough, including it in the preheader will drive home the message that there is a valuable money-saving coupon inside the email before it is even opened.

As in every other aspect of email marketing, the best and indeed only way to determine what works best for your brand is to test, test, and test some more. Just because your major competitor has adopted a particular preheader strategy does not mean that it will work for you. In fact, you have no guarantee that it’s working for them either!

The best preheader is both apothegm and sententia: a concise statement of powerful principle. Harness its potent capabilities and watch your email marketing metrics soar!