Often essays incorporate lists that pose challenges to manuscript design, paragraph structure and grammar. However, readers quickly grasp your point when you list subtopics or themes; assessment checklists; complicated lists of recommendations; steps in process analysis; or component parts of an item. Key aids in composing lists are punctuation and parallelism in grammar.
Introduce the list with an independent clause or a sentence with a colon before the list. In punctuation, the colon signals that a long list follows. If the list contains a series of one-word items, separate items with commas. If the list requires more separation between items, use semicolons to separate individual items of more than three words and items that contain commas.
Set off a short list from the rest of a sentence with a dash, an informal punctuation mark that also often marks a sudden or dramatic change. Example: All eyes share common features --- optic nerves, retinas and pupils. Use dashes sparingly in a formal essay. If you have to choose between using a dash and using a colon before a short list, use a colon. A dash has much in common with a T-shirt; neither signals high style.
Write an introductory sentence for steps in a sequence. Use numerals followed by periods for each step. Example:
To bake a cake:
Grease cake pans.
Use bullets to list items when order is unimportant. As always, provide a sentence to introduce the list to follow. Bulleted lists must warrant the use of space, meaning do not use bullets for a list of two to four small items. The reader may assume you are wasting space to make your essay appear longer.
If possible, ask your instructor or editor for style guidelines about preferred format. Beware of punctuating merely a list of items as a complete sentence. In grammar, parallelism requires that each item in a series begin with the same kind of word. Example: "Dogs can help with protection, with hunting and with detecting drugs" or "Dogs can track, swim and bark".
Do not use more than one bulleted list in a three-page essay, if you want your composition to look like a prose composition.