How to Build a Mailing List for Email Marketing

Email marketing is still one of the most profitable digital marketing channels available. While mailing lists take time to build, they are assets you own and control. Unlike social platforms where algorithms shift overnight, your email list provides a direct line to customers.

The real challenge isn’t just adding names to a contact list. It’s about attracting new subscribers who genuinely want to hear from you and will take action when your email campaigns reach their inbox.

In this guide, we’ll look at why email marketing in the UK is still powerful, how to build a mailing list that delivers results, and the common pitfalls to avoid.

The importance of email marketing

Email marketing continues to outperform many other marketing channels. According to industry studies, for every £1 spent, UK businesses can see an average return of over £30. That’s a strong argument for making it a core part of your marketing strategy.

The quality of your email list matters more than the size. A smaller, well-targeted group will often outperform a larger list that’s made up of unresponsive email subscribers. For companies working in B2B, investing time into curated b2b email lists means your message reaches people who are more likely to respond.

Another strength is control. A mailing list puts you in charge of timing, content, and targeting. Instead of relying on social media algorithms, you can run your own email marketing campaigns and track results with precision.

How to build out a mailing list

A good mailing list doesn’t appear overnight. It’s built through consistent effort, smart positioning, and giving people a reason to sign up. Let’s break down some of the most effective ways to do this.

1. Start with value-driven sign-up incentives

People rarely join a mailing list just to receive “updates.” They want something in return for their time and contact information. This could be a discount code, a free guide, early access to new products, or exclusive event invitations.

The more relevant your offer is to your target audience, the more likely they are to sign up to your mailing list. For example, a B2B software company might offer a detailed industry report, while a retailer might give first access to seasonal sales.

Always deliver on what you promise. If someone signs up expecting valuable content but only receives generic sales emails, they’ll unsubscribe quickly.

2. Create strategic sign-up points

Your signup form should be easy to find and simple to use. They can appear in your website header, footer, or blog sidebar. Pop-up forms can also work well if they’re timed so they don’t immediately interrupt the visitor’s experience.

Landing pages dedicated to signup forms are another effective tool. If you’re promoting an event or webinar, direct traffic to a page where signing up is the clear next step.

If you run in-person events, collect contact information from attendees who give clear consent. For UK businesses, always meet GDPR standards so your email list remains compliant.

3. Leverage your existing audience

You don’t always have to start from scratch. People who already follow you on social media, attend your events, or read your blog are prime candidates for your mailing list. Highlight the benefits of joining and make sure your signup form is easy to find across these touchpoints.

Your current email subscribers can also help you reach more people. Encourage them to forward campaigns to colleagues or friends who might benefit, turning your existing audience into a channel for gaining new subscribers.

For companies running email marketing in the UK, it’s important to use transparent opt-in language and clear consent options. That way, when your contact list grows, you know it’s built on trust and compliance.

Best practices for growing your email list

Once you’ve set up your forms and landing pages, the next step is keeping your mailing list engaged.

1. Keep your email list clean

It’s tempting to keep every contact you’ve ever collected, but inactive subscribers can harm deliverability. If too many of your emails go unopened, email providers may start sending your campaigns to spam folders.

Remove email contacts who haven’t engaged in several months. Before removing them, try a re-engagement email campaign with a clear offer or survey.

2. Segment and personalise

Not every subscriber should receive the same content. Segmenting your email list by factors like location, industry, or behaviour helps you send more relevant messages. For B2B companies, separating business to business email lists by sector can make campaigns more targeted and effective.

Personalisation goes beyond using a first name. Tailor your offers and content to what each group actually cares about. This increases open rates and conversions. A personalised email marketing campaign will almost always outperform a generic one.

3. Monitor and measure

Track your open rates, click-through rates, and conversion metrics. This data shows you what’s working and where improvements are needed.

For example, if your open rates are low, test new subject lines. If click-through rates are low, review your call-to-action placement or wording. Small changes over time can make a big difference.

Common mistakes to avoid when building lists

Even experienced marketers fall into traps when trying to grow their mailing list. Avoiding these will save you time and protect your reputation.

1. Buying email lists

Buying mailing lists might seem like a quick solution, but it’s usually a waste of money. Contacts who didn’t choose to hear from you are unlikely to engage. You also run the risk of spam complaints and GDPR penalties.

Building your mailing lists organically takes longer, but the subscribers you gain are far more valuable.

2. Overloading subscribers

Emailing too often can drive people away, especially if the content feels repetitive. Find a frequency that keeps your brand present without overwhelming inboxes.

Consider asking about preferences on your signup form to give them control, so subscribers can choose how often they hear from you. This simple step can reduce unsubscribe rates.

3. Ignoring mobile optimisation

Most emails are now opened on smartphones. If your emails aren’t mobile-friendly, you’re missing opportunities and frustrating potential customers.

Test your email marketing campaigns on different devices before sending. Keep subject lines short and ensure key messages appear early in the email.

From sign-ups to subscribers

A well-built mailing list is more than just a collection of email addresses. It’s a network of people who have chosen to connect with your business. 

Whether you’re building B2C or b2b email lists, the principles are the same, focus on quality over quantity. Because, when you focus on attracting the right audience, delivering value, and respecting their preferences, email marketing becomes one of your most reliable growth channels.

If you’d like help setting up your mailing list or refining your email marketing strategy, our team at believe.digital can create a plan that works for your business goals. 

Get in touch with us today or book a call and we’ll help you make every send count.