As a safelist user it's important to be aware that low open rates are common in our niche. 

The average member receives hundreds and thousands of emails every day, and this is really overwhelming for them.

Even though they stay your subscriber they stop reading your emails. This can happen for several reasons: they may have lost interest in your niche, they may be taking a break, or your copy is predictable.

Add here Gmail that enters the game and starts filtering your emails in the promotion folder, instead of putting them into the inbox.

People seldom browse that folder, so your message is buried among other rubbish.

The worst thing is if your emails receive low open rates then they are more likely to be filtered into the promotions folder...

where they get even fewer opens!

This February Gmail and Yahoo set new requirements for those who want to send bulk messages. Now you have to authenticate outgoing email, to avoid sending spam, and to make it easy for recipients to unsubscribe.

Otherwise you have big chances to be blacklisted and to lose email channel to communicate with your audience.

It's fairly easy to meet those requirements...

except the requirement to avoid sending spam.

You need to put some work so Gmail and your audience will not consider your messages as spam. 

One of the ways to do it is to keep your list clean and fresh. You need to delete all subscribers who have been on your list for over 90 days and have never opened a single email.

I recommend using a good email management system like AWeber where cleaning list is one of the standard features.

All you need to do is to filter subscribers by engagement and chose dormant as shown below: