Mistakes in email marketing can cause all kinds of problems. At best, you’re sending emails to subscribers who never turn into customers. At worst, you’re losing customers and have your email marketing messages blocked as spam. And you’re wasting time and money on what should be one of the cheapest, highest ROI marketing channels available. Here are 6 things companies get wrong about email marketing.

You Forget the Personal Touch

Email marketing will get relegated to the spam folder if you neglect the relationship with the customer. Lay the initial groundwork by welcoming your subscribers. Thank them for signing up for your email list. Consider making them feel appreciated by giving them coupon codes, discounts or free content. Send this immediately after they sign up, because these messages have the highest opening rate of any message.

You Don’t Segment Your Subscribers

It is a mistake to send the same marketing email to everyone on a single master list. Some subscribers want discounts and deals. Others want valuable content from the newsletter but don’t care about the latest sale. Your customers may fall into very different demographics, too.

Create email lists based on demographics, stages in the sale cycle, and customer preferences. When you segment your email marketing lists by interests and demographics, the open rates are forty percent higher and revenue is roughly 25 percent better. Segment customers by language and interests, and you’ll dramatically improve customer retention and sales.

You Neglect Mobile Users

Too many marketing emails are designed to be read on computers, though the majority of messages are now read on mobile devices. Check to see how your message will look on various smartphones. Send test emails to verify that call to action buttons work and images appear the way you expect.

Format messages so that they are mobile friendly. For example, avoid long blocks of text. Include images, but not too many, and not so many that emails take forever to load.

Not Sending Emails at the Right Time

This is another common mistake people make with email marketing. However, it’s important that you check variables like open rates and that you switch your schedule to see at what times you’re getting the best results. For instance, you could start sending mails every Thursday at 3pm for a month, then change your schedule by one variable. You can then start sending messages in the morning around 9am and see if there are significant differences. Just doing that will allow you to see if your subscribers prefer to get contacted in the morning or afternoon. Then you can start playing around with different days, cadences, and frequency.

You Don’t Include a Call to Action

Every email should have a call to action. Every email should have a clear purpose including an obvious action the recipient is supposed to take. Don’t send marketing copy without a funnel directing them to click on a link and buy. On the flipside, your email strategy should push customers to only take one particular action per message. This may be an incentive to buy, share the content on social media, refer a friend, or encourage them to sign up for a loyalty program. Don’t try to push them to take several actions; they will either take the simplest course of action or delete the message outright.

You Send Too Many Messages

Aside from welcome emails and messages with the status of someone’s order, you should limit how many messages you send, and ensure that they always have value to the customer.

For example, newsletters should always have content that is valuable to the customer, even if it is simply a breaking news item about stores opening in their area or upcoming sales. Limit these messages to once a week at most, and only then if it has clear value. If it isn’t of direct value to the customer, they’ll start deleting your messages and eventually unsubscribe. And receiving too many emails is the number one reason why people unsubscribe.

You Delay Campaigns

A surprisingly common mistake businesses make is delaying campaigns. They are planning a product release or holiday sale, but they wait to send marketing messages while hoping the email list will get larger. This is a mistake for several reasons.

First, it throws off the timing of your marketing content. Second, the email list may not get larger, but you’re missing the opportunity to sell to the customers who did sign up. Improve your message’s reach by asking your customers to forward the email or share content on social media.

Automating email marketing and dedicating hours to crafting the perfect message don’t matter if no one receives or opens the emails. Avoid these email marketing mistakes to see the 300 percent or higher ROI that email marketing can provide.