APA Title Case Rule

From APA’s Style Blog:

1. Capitalize the first word of the title/heading and of any subtitle/subheading;
2. Capitalize all “major” words (nouns, verbs, adjectives, adverbs, and pronouns) in the title/heading, including the second part of hyphenated major words (e.g., Self-Report not Self-report); and
3. Capitalize all words of four letters or more.