The best practices for conducting internal audits under ISO 9001:2015 include:

1. **Planning the Audit Schedule**: Develop a schedule that covers all areas of the Quality Management System (QMS) and ensures compliance with ISO 9001:2015 requirements.

2. **Planning the Process Audit**: Prepare by reviewing the standard, internal documentation, and creating a checklist of topics to cover during the audit.

3. **Conducting the Audit**: Perform the audit by asking questions, reviewing documents, and observing processes to gather evidence of compliance.

4. **Reporting on the Audit**: Report the results to relevant managers, highlighting any nonconformities and areas for improvement.

5. **Follow-up on Issues or Improvements Found**: Ensure corrective actions are taken and verify their effectiveness.

When addressing non-conformities, the organization should:

1. **Control and Correct the Nonconformity**: Take immediate action to address the issue and its consequences.

2. **Evaluate the Need to Eliminate Causes**: Determine the root cause to prevent recurrence.

3. **Implement Corrective Actions**: Take steps to eliminate the root cause.

4. **Review Effectiveness**: Verify that corrective actions have resolved the issue.

5. **Update Documentation**: Make necessary changes to procedures and records to reflect improvements.