2) Sponge inactive from active email addresses

As you begin to engage your subscribers, some subscribers have not to open your mail for some while

A subscriber who is in your mailing list for a good 6 months and did not deem it fit to open your mail is an inactive subscriber. You need to define your terms, deleting them is not the way to go.

Think of other ways of reaching out to them, you can create a separate campaign, if they are within your local market and you have their telephone numbers, you can reach out to them via text messages.

Be creative about it.

Create special offers that can help them take actions, this offers must be motivational and very different from your regular campaign in style and content.

Request from them, what you can do differently that will sere them better, in fact, you can ask them to unsubscribe

My advice remains are creative about it, your strategy should be targeted at bringing them back.

3) Avoid Inactivity: Send engaging Content

Sending relevant content at the right time is a good way to prevent inactivity; when we say relevant content, we mean content in line with your promise and your subscriber's need.

A properly delivered email, with good logo design looking presentable goes a long way, ensure your emails have a good appearance. Make them readable, avoid spelling errors and chuck text, the free version of Grammarly will be of very good help.

Talking about the frequency of your mails, it is all up to you; sending at least a mail per week is not a bad idea