From the AVP - 12 Steps for Enterprise Security Compliance

1. Install and maintain a firewall, IDS/IPS for data protection
2. Do not use vendor-supplied defaults for system passwords and other security parameters
3. Classify and then protect stored data
4. Encrypt the transmission of cardholder data and sensitive information across public networks
5. Use and regularly update antivirus software
6. Develop and maintain secure systems and applications
7. Restrict access to data by business need-to-know and encrypt highly restricted data in storage
8. Assign a unique ID to each person with computer access
9. Restrict physical access to cardholder data
10. Track and monitor all access (logical and physical) to network resources and cardholder data
11. Regularly test and assess security systems and processes
12. Maintain a policy that addresses information security