This section discusses and illustrates the basic conventions of American capitalization.
Capitalize the following:
The first word of a sentence: Some spiders are poisonous; others are not. Are you my new neighbor?
The first word of a direct quotation, except when the quotation is split: Joyce asked, “Do you think that the lecture was interesting?” “No,” I responded, “it was very boring.” Tom Paine said, “The sublime and the ridiculous are often so nearly related that it is difficult to class them separately.”
The first word of each line in a poem in traditional verse: Half a league, half a league,/Half a league onward,/All in the valley of Death/Rode the six hundred.—Alfred, Lord Tennyson
The names of people, of organizations and their members, of councils and congresses, and of historical periods and events: Marie Curie, Benevolent and Protective Order of Elks, an Elk, Protestant Episcopal Church, an Episcopalian, the Democratic Party, a Democrat, the Nuclear Regulatory Commission, the U.S. Senate, the Middle Ages, World War I, the Battle of Britain.
The names of places and geographic divisions, districts, regions, and locales: Richmond, Vermont, Argentina, Seventh Avenue, London Bridge, Arctic Circle, Eastern Hemisphere, Continental Divide, Middle East, Far North, Gulf States, East Coast, the North, the South Shore. Do not capitalize words indicating compass points unless a specific region is referred to: Turn north onto Interstate 91.
The names of rivers, lakes, mountains, and oceans:Ohio River, Lake Como, Rocky Mountains, Atlantic Ocean.
The names of ships, aircraft, satellites, and space vehicles: U.S.S. Arizona, Spirit of St. Louis, the spy satellite Ferret-D, Voyager II, the space shuttle Challenger.
The names of nationalities, races, tribes, and languages: Spanish, Maori, Bantu, Russian.
Words derived from proper names, except in their extended senses: the Byzantine Empire. But: byzantine office politics.
Words indicating family relationships when used with a person's name as a title: Aunt Toni and Uncle Jack. But: my aunt and uncle, Toni and Jack Walker.
A title (i.e., civil, judicial, military, royal and noble, religious, and honorary) when preceding a name: Justice Marshall, General Jackson, Mayor Daley, Queen Victoria, Lord Mountbatten, Pope John Paul II, Professor Jacobson, Senator Byrd.
References to specific presidents and vice presidents of the United States, but lower case references that are general: Vice President John Adams went on to become our second president.
All key words in titles of literary, dramatic, artistic, and musical works: the novel The Old Man and the Sea, the short story “Notes from Underground,” an article entitled “On Passive Verbs,” James Dickey's poem “In the Tree House at Night,” the play Cat on a Hot Tin Roof, Van Gogh's Wheat Field and Cypress Trees, Beethoven's Emperor Concerto.
The in the title of a newspaper if it is a part of the title:The Wall Street Journal. But: the New York Daily News.
The first word in the salutation and in the complimentary close of a letter: My dear Carol, Yours sincerely.
Epithets and substitutes for the names of people and places: Old Hickory, Old Blood and Guts, The Oval Office, the Windy City.
Words used in personifications: When is not Death at watch/Within those secret waters?/What wants he but to catch/Earth's heedless sons and daughters?—Edmund Blunden
The pronoun I: I told them that I had heard the news.
Names for the Deity and sacred works: God, the Almighty, Jesus, Allah, the Supreme Being, the Bible, the Qu'ran, the Talmud.
Days of the week, months of the year, holidays, and holy days: Tuesday, May, Independence Day, Passover, Ramadan, Christmas.
The names of specific courts: the Supreme Court of the United States, the Massachusetts Appeals Court, the United States Court of Appeals for the First Circuit.
The names of treaties, accords, pacts, laws, and specific amendments: Panama Canal Treaty, Treaty of Paris, Geneva Accords, Warsaw Pact countries, Sherman Antitrust Law, Labor Management Relations Act, took the Fifth Amendment.
Registered trademarks and service marks: Day-Glo®, Comsat®.
The names of geologic eras, periods, epochs, and strata and the names of prehistoric divisions: Paleozoic Era, Precambrian, Pleistocene, Age of Reptiles, Bronze Age, Stone Age.
The names of constellations, planets, and stars: Milky Way, Southern Crown, Saturn, Jupiter, Uranus, Polaris.
Genus but not species names in binomial nomenclature:Rana pipiens.
New Latin names of classes, families, and all groups higher than genera in botanical and zoological nomenclature: Nematoda. Do not capitalize derivatives from such names: nematodes.
Many abbreviations and acronyms: Dec., Tues., Lt. Gen., M.F.A., UNESCO, MIRV.
Adapted from: http://www.factmonster.com/ipka/A0771333.html and