A classification essay supports a thesis statement by grouping the supporting evidence according to shared characteristics. You select categories for a classification essay by choosing one classification method, such as size or cost, which provides an underlying connection for the categories and ideas presented. An outline helps you find a logical category sequence so you can build on your ideas and create an organized flow toward your conclusion.

Step 1

Develop your thesis statement. This is a statement about your topic that you intend to support with the body of your essay. "There are many types of fun vacations to enjoy during summer break" is an example thesis statement for the topic "Types of vacations."

Step 2

Create your categories by deciding how you want to classify the essay. For example, classify an essay about vacations by cost or destination type. Use categories like budget, middle ground and extravagant to classify by cost or categories like beach, family and adventure to classify by destination type.

Step 3

Brainstorm ideas that support your thesis. If your topic is "Types of vacations" and your thesis is "There are many types of fun vacations to enjoy during summer break," make a list of enjoyable summer vacations. Examples include going to a theme park or snorkeling off a tropical island.

Step 4

Organize your ideas by placing them into a category. For example, snorkeling off a tropical island fits under the categories of "beach" or "extravagant," depending on how you choose to classify your categories. Discard any ideas that do not fit into a category and any categories that have fewer than three ideas. Break apart categories with more than eight ideas to form two separate categories.

Step 5

Build your outline. Start with the Roman numerals one through three and list the words "introduction," "body" and "conclusion" next to each numeral. Note your main ideas under "introduction" and "conclusion," and list your categories under "body." Put a letter before each point and category on a new, indented line. For example, the letters A, B and C designate the first, second and third points under each Roman numeral. List your ideas under each category. Put a number before each idea on a new, indented line. For example, the numbers 1, 2 and 3 preceed the first, second and third ideas under each category.