A marketing plan is a blueprint that outlines how an organization plans to achieve its marketing goals. It involves analyzing the internal and external environment, setting objectives and strategies, and implementing a plan with defined responsibilities, timelines, and budgets. Key components include a mission statement, executive summary, analysis of customers and competitors, marketing strategies, and evaluation methods to measure the plan's success. Developing an effective marketing plan is a process that requires teamwork, simplicity, and regular feedback and revision.