If there's something most marketing experts agree on today, it's that you need an e-mail list to keep your website visitors and potential clients engaged. So you went and created an e-mail newsletter because everyone said you should do it – but then life happened, and you have not e -ailed the people on your list in a very long time.

In the online marketing lingo: your e-mail list got cold.

A cold e-mail list means your contacts do not remember who you are, why they've signed up in the first place, and what are the benefits of them staying subscribed to your list. If you send a sales letter to an an e-mail list you have not kept in touch with for months, some of these things may happen:

• You'll get confused answers asking who you are, and how you got their e-mail address.
• You'll get zero sales.
• You'll get a record number of unsubscribes.
• Many subscribers may report your e-mail as spam.

While your message was technically not spam because you abided by all the laws and regulations, it may not seem so to the subscriber. People sign up to different newsletters every day, and after a couple of months they do not even remember doing so. It's not even their fault – they did not receive a single reminder for months, maybe even years.

If this has happened to your list, there's no justification: I did the very same thing with not one, but two of my email lists. I have not sent a single e-mail to my subscribers in over a year, and naturally, some of them forgot about who I was and why I was writing to them out of the blue.

The first time I sent a newsletter to a cold list, it was disappointing getting barely any opens and clicks. The next time, I devised a strategy that kept my newsletter engagement high, and bought the goodwill of my subscribers.

I'll explain exactly how to do it in a bit, but before that, let's take a look at how you might prevent this from happening in the future.

Prevention tip # 1: Put a newsletter on your calendar

Make a habit of sending a monthly or weekly newsletter. Do not write only when you "feel like you have something to say", because it's illegally you will. If you commit to a schedule and your monthly newsletter send date is approaching, you'll miraculously find things to say in your e-mail. Deadlines are magical.

Set a schedule that's doable for you. Some may say that a weekly schedule is better than monthly, but the only "best practice" is the one that keeps you in the practice. If you keep struggling to make a weekly commitment with your newsletter, go for bi-weekly or monthly.

Prevention tip # 2: Create an automated e-mail sequence

There is no exact value after how many months will your list grow cold, but new subscribers will forget about you much faster than people who have heard from you multiple times. If a subscriber read a few of your e-mails and grow to like you, they will forgive you if you disappear for a while more readily than people who are taking a chance on you and do not know what your newsletter is normally like.

To give those new subscribers the best first impression of your brand, create an autoresponder sequence spaced out for about a week, a month, and two months from their first sign-up. You can add more e-mails to the list after that, but the first two months are critical.

Put your best foot forward in those e-mails. Write original, useful content that your readers will want to read and re-read. Curate the best articles you've ever written. Give them access to exclusive resources – not all at once (as this could overwhelm them), but drip them over a few weeks. Include a question or a call to action at the end of every e-mail to increase the reader's engagement.

Now that we've covered how to prevent your list from ever growing cold again, what do you do if your list is cold right now?

Follow these steps to warm up your subscribers and get them to like your brand even more than before.

1. Not everyone needs to know you were away

Tailor your e-mails. The "Sorry I have not written in such a long time" campaign does not need to go to all of your subscribers. If some of them just subscribed in the past month, they have no idea what happened earlier, and it's best to keep it that way.

In your newsletter provider application, create a segment that contains only the people who subscribed before a particular date (it can be 30 days or more), and send the campaign only to them. Make a separate campaign for the folks who subscribed recently containing only regular updates.

2. Remind people who you are and why they're getting this e-mail

Being forgotten hurts our ego, but it happens if you do not make an effort to stay top-of-mind. Anthropological research has shown that the human brain is only capable of managing a limited number of relationships (some scientists place this number around the 200 mark).

When sending a warm-up campaign, the first thing you need to do is remind people who you are, and why they initially signed up to your list. Remind them of the benefits you've promised them which have prompted them to give their e-mail address away, for example: "I hope you've enjoyed the [Free Report Title] I've sent you as a thanks for signing up . "

If they remember that they've received value from you in the past, they will be more likely to stick around on your list.

3. Apologize for not writing in a long time

Make it short, and do not make any excuses. Just admitting to making a mistake shows your humanity to the reader. Everyone does something we're not proud of sometimes, and they'll be able to empathize.

4. Include a "Welcome Back" gift

There's nothing like a freebie to warm up your subscribers' hearts. Think about something that your subscribers will consider valuable, and give it to them with no strings attached. This can be an eBook, a workbook, a cheat-sheet, a video tutorial, access to an exclusive teleclass, a set of wallpapers, a printable coloring page, or something else that's relevant for your audience.

You may feel that you're giving away too much. You're not – what you're doing is investing into a relationship. If these people are gone from your list because they do not see any value in it, they're gone forever. Those are lost opportunities for building a long-lasting relationship with a faithful audience that will support your work down the line.

Make sure the gift is something really free, not a discount on a paid service. It's not likely that they will want to spend money on your offers yet, but you can use the discount incentive for your next campaign.

5. Set expectation for what's to come

Up to this point, you've only worked to get on the subscriber's good side. Now is the time to close the deal.

Many people might still unsubscribe, and your e-mail has only provided them a reminder to do so. These people would probably not receive value from your newsletter anyway.

What we need to do now is to convince people who would receive a great amount of value to stay subscribed. You can do this with a teaser of future campaign content. If you've committed to warming up your list now, this means you have a plan for what you want to send to your list in the future. State your plans in a short paragraph to create anticipation. If the content you're promoting your readers interests them, they will want to remain subscribed.

6. Make good on your promise

Once you've sent your warm-up campaign, cross your fingers and wait. There will be some unsubscribes, but that's normal and it does not mean you did anything wrong.

After a week or two, continue with your regular e-mails. Make sure you include the content you've promised them in step 5, and continue to go above and beyond until your rates are healthy again.

Show respect to your newsletter subscribers, and they will start respecting you. Think of them as people, not as data in your contacts database, and you'll find more inspiration and motivation to continue publishing valuable, useful content regularly.