Identify where you can improve your email newsletter:

Frequency: Are you bombarding your customers with too many emails? This is a common problem where you have seen response rates drop over a period of time.

Content: Are your offers and articles appealing enough? How does your content compare to the competition?

Relevancy: This is the biggest problem with most email newsletters and another reason why you may see results drop over time. If the emails you send through have nothing relevant for a recipient why would they click-through? Relevancy can be resolved in a number of ways including: sending to segments of your database each time rather than the whole list, using past email behavior to determine interest and using tailored content blocks or dynamic content.

Deliverability: Quite simply if your emails are not getting
into the inbox or being labelled as junk it does not take a genius to
work out that fewer people will open the email and even fewer will
click-through. Take proactive steps by ensuring your email provider is
whitelisted and not blacklisted and that your email has been scored in
a spam checking tool. If you are sending from an in-house system you
may find that an outsourced email newsletter software solution will
improve your deliverability.

Rendering: Many email newsletters land in our web-based email
clients inbox looking mangled. Not only does it look unprofessional it
is also difficult to read and hence less likely for the reader to be
able to find something worth clicking on. Make sure you are not having
these issues by reviewing our HTML for emails guide.

Data Collection: How ‘opted-in’ are members of your list?
Those that might have subscribed while entering a competition are less
likely to be responsive as those that pro-actively requested your
information hence you will see this come through in your campaign stats.

Email creative: In particular what you should look at here would include:

• Call-to-actions – are they obvious?
• Does you message take into account the preview pane and the fact that the top 300 pixels are the most important
• What does your email look like with image blocking enabled?

Source: bytestart.co.uk