Types of audits
Internal audits (first-party) check conformance to your own QMS and to the standard you're certified to. Supplier audits (second-party) verify a supplier's process and quality system before approval and periodically thereafter. Certification audits (third-party) are performed by a registrar. Layered process audits (LPA) are short, frequent checks performed by multiple layers of management directly on the production floor.
Audit findings and corrective action
Every nonconformance from an audit triggers corrective action with the same rigor as a customer complaint: containment if applicable, root cause investigation, documented corrective action plan, verification, and effectiveness check. Weak responses to audit findings are themselves a finding at the next audit.
Preparation discipline
Successful audits aren't about preparation in the week before — they're about a quality system that runs the same way every day. The most useful preparation is honest internal auditing throughout the year and disciplined closure of every action item.