To develop an internal audit plan that aligns with ISO 9001 standards, focusing on the most critical areas for compliance, follow these steps:

1. **Conduct a Gap Analysis**: Determine the extent to which your organization already complies with ISO 9001:2015. This will help identify areas that need more focus.

2. **Establish an Audit Schedule**: Plan when audits will occur, ensuring they cover all areas of the QMS over time.

3. **Define Audit Objectives and Criteria**: Consider the purpose of the audit and what you need to know. Define the criteria based on ISO 9001 requirements and your organization's internal procedures.

4. **Plan the Process Audit**: Identify which processes are most critical and have the highest probability of nonconformities. Focus on complex processes and those with significant impact on quality.

5. **Prepare an Audit Checklist**: Review documented information such as standards, records, and procedures. Write questions that will help you gather evidence on compliance and effectiveness.

6. **Assign Competent Auditors**: Ensure auditors are trained and do not audit their own work to maintain objectivity.

7. **Conduct the Audit**: Follow the planned path, ask prepared questions, and gather evidence.

8. **Report on the Audit**: Communicate results to relevant management and document findings.

9. **Follow-up on Issues**: Address any nonconformities or areas for improvement identified during the audit.

10. **Review and Improve**: Use audit results to improve the QMS and prepare for future audits.

By focusing on these steps, you can ensure your internal audit plan is comprehensive and aligned with ISO 9001 standards.