Note: Upon her indictment on federal money laundering charges and her arrest February 8, 2022, Inc. dismissed Heather Morgan as a contributing columnist. As is our practice, we do not unpublish editorial content, and rather have added this note for full transparency.

So you've invested time in researching your prospective customers, writing an email that addresses their problems, and making sure to include an enticing subject line and lots of benefits in that message.

And yet, the only replies you seem to get are vacation auto-responders.

One of the biggest reasons situations like this occur is because people hit all the other requirements for a good sales email, then forget to end the message with a compelling call to action. Without a strong call-to-action, it won't matter how many people open your emails--you never gave them a crystal-clear reason to respond, so they probably won't.

In sales emails, the call to action needs to indicate exactly what the other person must do to continue the conversation, and what they'll get in return for taking that action.

Here are three things to keep in mind when writing any call to action, sales emails or otherwise.

1. Ask a question.

While it might seem obvious, many of us often forget the power of a simple question.

For example, asking someone's thoughts on an industry statistic is an easy way to make them feel like part of an actual conversation: "The average e-commerce conversion rate is roughly 2%. Does your team have a strategy in place to improve upon that average?"

Another idea is to appeal to the prospective customer's vanity and ask for their opinion or advice: "I would love to talk about this with someone of your expertise. When do you have time for a call next week?"

You could also remind the prospective customer of a particular pain point they have, like the dangers of losing revenue or the company's security getting hacked. By doing this, you can then introduce the benefit your service or product provides and position it as the answer to their problem. Just make sure the pain point you're trying to solve is actually relevant to their line of work.

2. Offer something of actual value.

Underscore that word "value." Nobody wants to see your demo included at the bottom of the email, or even a request to share it.

Instead, use the research you've already done on your prospective customers to determine what they would actually find valuable. What are their problems and how does your product or service solve them? If they worry about wasting money on bad hires, don't simply ask if they're interested in hearing about your job interview software. End your email with something like, "When do you have time to learn more about a faster, more accurate way to find the best candidates?"

Adding some kind of value to your calls to action also helps build up your own credibility and reputation, especially if you can then deliver on that value during a phone call or meeting. When people understand that you respect their needs and time, they're far more likely to take your call to action seriously.

Under no circumstances should you use the call to action (or any other part of the email, really) to rattle off a list of features you think are cool. That's the opposite of valuable, and could ruin an otherwise enticing email.  

3. Don't overwhelm the other person.

Two of the most common ways to ruin a call to action are asking for too much and making it too long.

Asking for too much basically means you're including multiple asks in a single call to action: "Check out the links below for more info. I've also included a brief video you can watch. Let me know when you have time to talk next week."

Reading that call to action, your prospective customer won't know which "task" to do first, and will probably feel overwhelmed and do none of them. And were they to pick one, the action you want most--a response--is at the end of that list. So there's a high chance the other person will click on your link and wind up somewhere on the web instead of in your inbox.

Length is another issue I see a lot with calls to action. Simpler is better when it comes to this last part of your email. Sometimes, a simple "When do you have time this week to talk?" will do. Never send a call to action that's longer than a couple sentences, and even then, reread to see if you can cut those two into a single line. The shorter the call to action, the higher the chance of holding the other person's attention.