A successful phishing attack requires success during the first four stages, providing you with opportunities to prevent, detect, and respond before the attacker has an opportunity to establish a foothold. An attacker’s first activity is to observe your company, likely starting with something as simple as a Google search, and the goal is to understand how to breach the organization. You need to understand whom the attacker is likely to be targeting, and how to decide exactly what can be delivered. You also need to train your employees to report suspicious emails as quickly as possible.
Source: https://www.helpnetsecurity.com/2021/04/27/defend-organization-phishing-attack/