Sending an email newsletter to customers, clients and prospects can be a great way of marketing your business.

But there are easy mistakes to make which can annoy your customers and could even mean you end up on the wrong side of the law. Here are the top seven things not to do when sending email newsletters:

1. Don’t spam everyone you know
You need to put effort into building your subscriber list. It’s very important your customers and prospects agree to receive your email newsletter before you send it to them.

Take time to build a quality list of both active and prospective customers. Use every possible customer interaction to invite them to receive your email newsletter – client visits, phone conversations, trade shows, your website, LinkedIn, etc. You may start with a few dozen subscribers but you’ll have hundreds within the first year if you make it part of your day to build your list.

2. Don’t use your own computers to send your email newsletter
If you send newsletters from your personal PC or server, there is a much greater chance that the email will be marked as “spam”. There is also a chance your IP address might be “blacklisted”, which means all of your day-to-day emails are much more likely to be caught as spam.

Many companies send their email newsletters via large cloud-based email providers like MailChimp and Campaign Monitor because these services are secure and can overcome a black-listing event.

3. Don’t attach your email newsletter as a PDF
Your online newsletter should appear as soon as the recipient opens their email. If you instead choose the ‘old school’ method of attaching it as a downloadable file, your readers are 40% less likely to read it. File downloading is not ideal, especially on mobile devices or from within businesses with tight email security policies.

Our research suggests that 92% of readers would rather view the newsletter in the email body than download an attachment. Meanwhile, 76% of business professionals surveyed believe companies who attach their newsletter as a PDF are “behind the times”.

4. Don’t cram in too many words
Most of us are time poor so we tend to skim newsletters. Make your email newsletters easier to read by separating your articles with images and white space. Each article should feature a catchy headline and a brief synopsis so the reader can click-through to the website to read more if they are interested. This technique also allows you to measure clicks, so you can see which topics resonate best with your audience. Your articles should be punchy (no more than 600 words) with clear sub-headings. Avoid long blocks of text.

5. Writing good quality content
Readers will soon tire of emails that are poorly written or contain irrelevant content. It’s good to personalise your newsletter with local happenings (e.g. a new staff member) but don’t overcrowd it with this type of material. Spend time to plan your content and always proof-read it (and use a spell check!) before you send.

Don’t write too technically – the language you use in your email newsletters should be understood by primary school students. Remember, you are the expert in your field and your readers don’t want too much technical information – that’s why they rely on you.

6. Don’t send your email and then forget about it
Instead, you need to track your results. Take the time to review your results so you can learn about what your readers are interested in. You should expect at least 25% of your recipients open your email as this is a reasonable benchmark for a “unique open rate”. If you are writing interesting clickable content then expect at least 15% of those who open will click-through to read more. Compare your results for each and take note of the articles that get the most clicks. The article you post at the top of your email will naturally perform better than others (your readers don’t like to scroll).

7. Don’t forget why you are writing in the first place
If your goal is to write email newsletters to stay top-of-mind with your customers and prospects then make sure you include your company logo and contact details in both the email and on the landing pages. To maximise the number of enquiries you receive we recommend that each article should have a corresponding enquiry form to make it easy for the reader to contact you.

A final thought. We often get asked the question “how often is too often?” when sending email newsletters. Too often and your readers might get sick of you, and you will see more readers unsubscribe. Meanwhile, if you send too infrequently, you will notice less people open your emails.

Our statistics show the best performing email newsletters are those that are sent monthly. If you only send your email newsletter once a quarter or bi-annually then you are missing a marketing opportunity.

Joel Montgomery is the founder and managing director of digital marketing company Affiniti.