Data breaches from email attacks have been an issue since email was first implemented. Common attack methods like phishing are still a threat to organizations to this very day. That is because it never seems to stop evolving and keeps becoming more and more convincing. Email compromises have caused billions of dollars in damage worldwide, and it shows no sign of stopping. The purpose and research questions of this thesis are formulated to find guidelines or solutions that organizations can follow to improve their overall email security and awareness. In this thesis, both a systematic literature review and interviews are methods used to conduct the research. That way, both the technical portion of the subject, as well as the human perspective are covered. We found that the most common and significant email threats to organizations are phishing, BEC, and APT attacks. This thesis provides methods to mitigate these threats. What has also become clear is that human mistakes are a large portion of the problem concerning email attacks.