An English Handbook for Writers, Students, and Teachers
Always capitalize the pronoun, I, even in contractions like I’ve, I’ll, and I’m.
Capitalize the first word of a quoted sentence, even if you already capitalized the first word of your own sentence. For example: We heard Beyoncé say, “Go get me a mocha latte, please.”
Capitalize all proper nouns, like place names, people’s names, the name of a company, the name of a club, the name of a historical event, religions, languages, the name of a street or town, etc…
Capitalize all proper adjectives (examples: French bread, Flintstone vitamins, Micron computer).
Common animals, like domestic dogs, black bears, and stingrays, do not need capitalized, but if the breed of animal uses someone’s last name or the name of a place (like Doberman pinschers, French poodles, and Labrador retrievers), then the names of people and places must be capitalized within the breed.
Certain technology-related brand names capitalize the second letter of their name instead of the first letter. This is called “camel case” (instead of upper-case or lower-case). Some examples of these brand names include iPod, iBook, iMac, iPad, and iPhone.
Capitalize people’s titles. For example, Mr. Bean, President Lincoln, Dr. Dre, and St. Patrick. However don’t capitalize these words if they’re not with a name (as in I wrote a letter to the president.)
Capitalize family titles (mom, dad, etc.), if you could replace it with a name and it works. Here’s what I mean: In a sentence like “We’re going to Grandma’s house,” you could have said “Ruth’s house,” and it still sounds fine, but if you had said, “We’re going to my grandma’s house,” it would sound silly to replace it with “my Ruth.”
Capitalize days of the week, names of the months, and holidays. This rule doesn’t hold true in Spanish though, so if you’re bilingual in Spanish and English, please keep this in mind.
Capitalize the first, last, and all important words in a title. Here are some examples: Pirates of the Caribbean, “Just the Way You Are,” and Times-News.
Capitalize the greeting and closing of a postal letter. For example, capitalize Dear Dr. Oz, and capitalize the first word in the closing, Sincerely yours, as your letter comes to an end. E-mails are generally less formal, but greetings and closings are sometimes used with e-mails, especially if it’s the first e-mail ever sent to the recipient. See more under the heading “E-mail.”