Spam filters are fairly straightforward. There is a long list of factors emails are scored on. If the email’s score gets too high, it’s flagged as spam by the email server. Unfortunately, every server is different and constantly changing. So what’s marked as spam on one server might not be marked as spam on another. As a general rule, you’ll want to avoid:
When it comes to designing an email for a specific offer, the main component to keep in mind is the offer itself. You want the copy to be brief but descriptive enough to convey the offer's value. In addition, make sure your email's call-to-action (CTA) link is large, clear, and uses actionable language. You can also include a large CTA image/button underneath to make the action you want email readers to take crystal clear.