General Rules:
* The first word is always capitalized.
* The last word is always capitalized.
* All nouns are capitalized.
* All pronouns are capitalized.
* All verbs are capitalized.
* All adjectives are capitalized.
* All adverbs are capitalized.
* All conjunctions are capitalized.
* All prepositions are capitalized.
* All articles (a, an, the) are capitalized.
Exceptions:
* Articles (a, an, the) are not capitalized if they are the first word of the title, unless they are followed by a proper noun. For example, "The Cat in the Hat" is capitalized, but "A Cat in the Hat" is not.
* Prepositions and conjunctions are not capitalized if they are less than four letters long, unless they are the first or last word of the title. For example, "The Cat and the Hat" is capitalized, but "The Cat on the Hat" is not.
* Some titles, especially those that are short or informal, may use all lowercase letters. For example, "the cat in the hat" or "the cat on the hat."
Specific Cases:
* Subtitles: If a title has a subtitle, the first word of the subtitle is capitalized, and the rules for capitalizing other words in the subtitle are the same as the rules for capitalizing words in the main title. For example, "The Cat in the Hat: A Story for All Ages."
* Proper nouns: Proper nouns, such as names of people, places, and things, are always capitalized. For example, "The Adventures of Tom Sawyer."
* Numbers: Numbers are generally not capitalized in titles, unless they are part of a proper noun or are the first word of the title. For example, "The Seven Dwarfs" is capitalized, but "Seven Dwarfs" is not.
Other Factors:
* Style guide: Some style guides, such as the Chicago Manual of Style or the Associated Press Stylebook, may have their own rules for capitalizing words in titles.
* Personal preference: Ultimately, the decision of whether or not to capitalize certain words in a title is a matter of personal preference. However, it is generally best to follow the general rules and use common sense.
It's always best to check the style guide you're using for the most accurate capitalization rules for your specific situation.