To ensure comparability and consistency between their interim financial statements and their annual financial statements, companies can take the following steps:

1. Consistent Accounting Policies: Companies should use consistent accounting policies between their interim and annual financial statements. Any changes in accounting policies should be clearly disclosed and explained in the notes to the financial statements.
2. Similar Reporting Periods: Companies should use similar reporting periods for their interim and annual financial statements, such as quarterly or semi-annually, to enable comparison of financial performance and position.
3. Consistent Format: Companies should use a consistent format for their financial statements, including the presentation of line items and notes to the financial statements, to facilitate comparison between the interim and annual financial statements.
4. Comparable Disclosure: Companies should provide comparable disclosures in their interim and annual financial statements, including information about significant accounting policies, risks and uncertainties, and related party transactions.
5. Review and Audit: Companies should ensure that their interim financial statements are reviewed or audited in accordance with the relevant professional standards, to provide assurance about the accuracy and completeness of the financial information presented.
6. Internal Controls: Companies should have appropriate internal controls in place to ensure the accuracy and completeness of their financial information, both for interim and annual financial statements.

Overall, ensuring comparability and consistency between interim and annual financial statements is important to provide stakeholders with reliable and accurate financial information about the company's performance and position, and to enable informed decision-making.