1. Keep your system updated with the latest security patches and updates.
2. Implement strong password policies, including password complexity and regular password changes.
3. Use strong authentication methods, such as multi-factor authentication, to prevent unauthorized access.
4. Limit access to sensitive data by using role-based access control and least privilege principles.
5. Enable Windows Firewall and configure it to block unnecessary ports and protocols.
6. Use encryption to protect sensitive data at rest and in transit.
7. Implement security auditing and monitoring to detect and respond to security incidents.
8. Use antivirus and anti-malware software to protect against viruses, malware, and other malicious software.
9. Harden your system by disabling unnecessary services and features, and by using secure configurations.
10. Regularly perform security assessments and penetration testing to identify vulnerabilities and strengthen security controls.

By following these Windows Server 2019 security best practices, you can help ensure the security and integrity of your system and protect against potential threats.