How do I stay off email blacklists?

Assuming that you are not the guilty party, eg the considered sender of spam, and you have secured your server correctly.  The likelihood is that you are the victim of being judged guilty by association.  This normally happens when you use a shared email service, or a shared IP address. There are various providers that maintain blacklists and the first step is to confirm which list you appear on, the second is confirm why, and the third is to resolve the situation and then notify the list administrator.

The monitoring of blacklists is a facilty that we can provide as part of our proactive computer support services. Microswift also provides managed e-mail services for clients that prefer us to host their email on one of our servers.  If you are a business with 5 or more users then probably the most effective solution is to have your own email server and dedicated IP address configured correctly.