Determine the types of sections your paper needs. Sections can be used to separate different topics within a paper or to delineate multiple aspects of the same topic. Writing a basic tree-structure outline for your paper can help you identify various sections that can be used as headings in your paper.
Use level one heading for main ideas. APA style mandates that level one headings are centered on the page in bold typeface using title case. Level one headings are used to separate each topic into discrete sections. Ideas related to this section are listed with subordinate headings -- levels two through five.
Support your main ideas with level two headings. Sections that have supporting topics can be identified with level two headings. For example, if you are writing about items on a McDonald's menu, use "Menu Items" as the level one heading and "Burgers," "Fries" and "Desserts" as level two headings. Level two headings are aligned on the left margin in bold typeface using title case.
Divide level two sections into subsections. When you need to specify attributes of a section's subsections, use level three headings. Level three headings must be indented and use bold typeface. In addition, level three headings are given standard sentence capitalization -- first word and proper names only -- and end with a period.
Use level four headings to create subordinates to level three headings. Level four headings are displayed with the same formatting as level three headings with one addition: italics.
Add level five headings when necessary. Level five headings are used to create sections under level four headings. Of all five APA style headings, level five is the only heading that does not use bold type face. This distinction is the only formatting difference between level five and level four.