Look at the layout of an APA style outline to get a better idea of the format. (See Resources)
Begin an APA outline with a heading prefaced by a Roman numeral. All points or topics belonging under that first heading should be prefaced with a capital letter and indented once. If there are additional points under the second heading, begin those with a number and indent an additional time, and if points belong under that, begin those with lowercase letters and indent again.
Start with the most general information under the Roman numeral headings. All the points below those headings should gradually become more specific.
Example:
I.
---------> A.
-------------------->1.
-------------------------------->a.
Write headings containing information of similar significance so that they are prefaced by the same symbols (Roman numerals, uppercase or lowercase letters, etc). The subheadings that follow should uphold the same pattern, so points under capital letters should have a similar level of significance within the document, as should points under numbers and lowercase letters.
Write headings and subheadings using a similar structure. For example, if your first heading reads "Search the Library Database," the next heading should also begin with a verb, and could read "Choose Appropriate Resources to Investigate," and subheadings should follow suit. For academic papers, it might not be appropriate to use headings and subheadings with such direct verbs and directions. If writing a psychology research paper, for example, the first heading could list a basic psychiatric disorder, such as depression, and subheadings could delve into symptoms, diagnosis, treatment, etc.