Global accounting firm KPMG recommended 10 procedures to make an audit committee successful. These procedures include: be a catalyst for improving risk management, closely monitor management disclosure, get up to speed on fair value and other accounting standard developments, make sure that the CFO and accounting and finance departments have the resources to do a good job, assure a shared vision of internal audit, encourage frequent communication with the external audit partner, be prepared for a crisis, make sure the full board of directors knows the plans and needs of the audit committee, assess the tone at the top and do a through self-examination of audit committee performance.
All these KPMG procedures are appropriate and worth implementing (if not already in place). Sam Antar would add one more--intensely scruntize all documents provided by management, especially if the committee has been given even a iota of a reason to be concerned about management integrity.
UPDATE: Thanks to Sam Antar for the additional recommendations included in the Comments Section!