What does a good email security program mean to you?

I hear about many domains of security but rarely about email security. I'm curious what everyone is doing for email security?

Idea's I've seen/used:

* Use secure protocols (SSL/TLS)
* Security awareness training (phishing, social engineering, etc..)
* Enabling SPF, DKIM, and DMARC for outbound security...having a tool provide stats on how you're and when things look odd
* Spam/phishing filtering
* DLP

awareness awareness training cybersecurity dkim dlp dmarc doing domains email email security engineering etc phishing program protocols security security awareness security awareness training security program social social engineering spam spf ssl things tls tool training