When writing out titles, there are a few capitalization rules you should keep in mind. I do want to point out that a few style guides only require the first word to be capitalized. For most others, these are the basics:
- Always capitalize the first and last word of a title no matter how insignificant or short.
- Capitalize all verbs (including be, is, are, was, were), nouns, pronouns, most adverbs, and adjectives. Many grammar books simply call these “significant” or “important words.” If it seems important, it’s probably capitalized.
- Do not capitalize most short words: coordinating conjunctions (and, or, nor, for, but), articles (a, the), as, to, and most prepositions—unless they’re the first or last word. However, the you-knew-it-was-coming exception is . . .
- You can (and probably should) capitalize any word that’s six letters or longer (some people say five), no matter what kind of word it is. For example, prepositions such as through and underneath can be capitalized because of their length.
- Do not capitalize words that have to be lowercase for another reason. The main place you’ll need to know this is with the scientific name of an organism. When writing them out normally, you capitalize the genus and lowercase the species (e.g., Yersinia pestis). Do the same in titles.
As I mentioned, these rules are not universal, though they are common. You should always do some research on what a particular journal, publisher, magazine, or website expects if you’re seeking publication.
Update (9/20/10): I should point out that some style guides recommend not capitalizing be, is, are, was, and were because they are linking verbs. I find this argument to be weak, since other linking verbs are capitalized (for example, seem). However, refer to your style guide for the final determination.
I think that many of us suffer from hypercorrectionism. Wanting to make our work perfect, we tend to “over-fix” what doesn’t need fixing. This is especially true in the use of who vs. whom (more about this later) and in capitalization. Some things do not need capital letters, but I see a few specific grammar-tripping issues frequently. So, let’s take a look at the main ones that cause consternation.
- Seasons: Perhaps this rule is odd, given how we capitalize months and days. However, seasons are not. It’s spring, summer, fall, winter.
- Directions: Compass directions are not capitalized. If you mean that someone is to look or go in a specific direction, keep it lowercase (just as you wouldn’t capitalize up or down). The confusion stems from the capitalization of specific geographical regions. We say that someone lives in the Northeast (the region of the U.S. starring New York, Maine, New Hampshire, etc.), which is capitalized.
- General nouns: Unless a noun is standing in as the name for someone, we don’t capitalize. Dad, for instance, is only capitalized if it is naming your father specifically without using a pronoun (I see Dad got into the Wii we bought him). Other peoples’ dads get the lowercase treatment (his dad). The same is true of honeys, snookies, and cupcakes. Capitalize only when standing in for a name.
- The name of this planet: In most cases (let’s say 95%), you don’t capitalize earth. It’s odd but true. The only good exception is when our planet’s name is listed with the specific names of other heavenly bodies (e.g., Venus, Earth, Jupiter)—and this is mainly for consistency. Some grammar guides make an issue of whether it’s the dirt or the planet, but finding the line of demarcation there is trickier than you think. Stick with lowercase.
I hope these help in your own editing.