Be sure you include all items that belong in your classification. Be sure you present your categories in a logical order. Don't overlap categories. Introduction is at least one paragraph and contains a clear thesis statement. Introdution introduces the main points that will be expanded upon in the supporting paragraphs.
Introduction invites the reader in.
Supporting paragraphs must each begin with a clear, underlined topic sentence. All other sentences in that paragraph must be relevant to the topic sentence. The paragraphs are well developed. All paragraphs are presented in a logical order and tie in to the overall organization of the essay. Conclusion must be at least one paragraph.