Send your newsletter often enough so Subscribers do not forget who you are.

If they don't even remember that they subscribed to your newsletter, they may simply unsubscribe from your List. Worse yet, they may just click the Spam button and create deliverability issues for your other Subscribers.

Before you sign up a Subscriber, make sure you properly set their expectations.

Let them know in advance how often you will be sending messages and what type of content they can expect. You only want those people to sign up who are actually interested in receiving your newsletters.

Make sure you only send content they are expecting to receive.

If later, you decide to send a different type of content, seek their permission first. Ask if they want to remain on your List. Otherwise, they may simply unsubscribe or report it as Spam.

If you set the expectation of 1 newsletter per week, then make sure you do that.

If you are unable to send your newsletter during a certain week, it would help to send a message letting your Subscribers know why. Also, let them know when they can expect your next newsletter.