Defining KPIs

As a successful business consultant specializing in <industry>, identify and elaborate the most critical metrics to track and the most crucial Key Performance Indicators (KPIs) for a business in this sector. Your selection should cover financial metrics, customer-centric metrics, operational efficiency metrics, and employee performance metrics, where relevant. Also, provide a brief explanation of how each KPI contributes to business success, how to interpret it, and actionable strategies for improvement, should the need arise.