Keep the subject line and pre-header short: The subject line is crucial. Keep it short so the reader knows exactly what the email topic is about. And the pre-header text (also known as snippet text), don’t let it go to waste by using “To view this email in your browser…”. Instead, summarize the email or include a call to action (i.e., Use “FREESHIP” to get free shipping).
That isn’t to say that sales-y promotions couldn’t ever create results—as marketing “gurus” have proved. The results just aren’t as good as they could be. Take the biggest gurus’ results—the ones they boast about—and calculate their conversion rates. Often their marketing is comparatively ineffective. They just have massive volume, so the sales numbers are impressive.