A thorough essay can be written with four to five main aspects for your outline. While you can word each heading more specifically, think in terms of having a Summary, Introduction, Problem, Solution and Conclusion. Under each of those headings, write two to three "bullet points" that will make up the content. After you complete your outline, go back and connect those points into complete and coherent sentences. A way to test your points for completeness is to read your outline aloud, filling in the blanks orally, as though you are giving a speech. Each bullet point should provide you with enough of an idea that you can form a complete sentence in your head and talk about that particular heading.
Your analytical essay can analyze an existing marketing plan for its structure, or critique the plan's effectiveness. Analyzing the structure is merely a matter of breaking down its components: Did the Executive Summary effectively introduce the company and explain its objectives? Were the Strengths, Weaknesses, Threats, and Opportunities supported by facts and outside research? Was the Competitor Analysis thorough? When composing an essay of this nature, you could organize your outline in terms of Executive Summary, Situation Analysis, Anticipated Goals, Actual Goals, Weaknesses and Recommendations.
Think of an academic essay as instructional. You -- or your audience -- can find many examples of a marketing outline in business publications or through online resources. Your essay should "walk" your audience through the components of a marketing plan or program. Some possible aspects to outline for this essay might include: Setting Realistic Goals, How to Use Demographics, Determining Your Internal Strengths, Differentiating an Opportunity From a Threat, Setting a Realistic Price and Conducting Your Own Research.
A descriptive essay could be a top-level examination of the purpose of marketing -- not necessarily the marketing plan. This type of essay is useful if you are explaining to someone what a career in marketing might entail. A top-level outline may include a Definition of Marketing, Components of Marketing, Education Requirements, Careers in Marketing, Current Opportunities in Marketing and Opportunities for Advancement. A more detailed essay could be done using any of those outline elements as its own subject.