Marketing control involves measuring marketing performance against plans and taking corrective action when needed. It is a cyclic process with four main steps: 1) Establishing performance standards, 2) Measuring actual performance, 3) Comparing actual performance to standards and evaluating any deviations, and 4) Taking corrective actions to align performance with standards. Effective marketing control provides accurate and timely information, focuses on strategic areas, is economically realistic, coordinates with organizational workflows, is flexible, and is accepted by organizational members. It helps monitor performance, locate issues, update information, reformulate plans, and adapt to the environment.