Executive Summary: the marketing plan like all the documents that are submitted to established executive bodies must begin with a brief summary of the whole plan, with basic numerical data and info. Mission and Vision: the marketing plan includes the company's "reason of existence", values and its future intentions and strategic approach.
Sales and Strategy Forecast: If you have a target to achieve you can plan out your work according. It's just like keep the figures real and amenable. Unrealistic figures would not help you ever to get the target on time. Secondly with these forecast, you can compare your marketing strategies and come up with the best solutions for future activities.