The general principle with capitalization is that proper nouns are capitalized and common nouns are not.
Capitalize proper nouns and "proper" adjectives. Proper nouns are the names of specific persons, places and things.
For Example: Virginia Woolf, Mississippi.
"Proper" adjectives are words that act as part of the noun.
Example: the Golden Gate Bridge, New Orleans.
Common nouns are words like: bridge, state, author, month.
Adjectives are words like:
Capitalize days of the week, months and holidays.
For example: Monday, November, Christmas.
Capitalize historical events, documents, periods, and movements.
For example: the Vietnam War, the Constitution, the Renaissance, the Romantic Movement.
Note: The article "the" that precedes the historical terms is not capitalized.
Capitalize government offices or departments and institutions.
For example: House of Representatives, Department of Homeland Security, Hoboken Municipal Court, John F. Kennedy High School.
Capitalize specific places and geographical regions.
For example: New York City, Empire State Building, Hoover Dam, Beijing, the Nile River, the Northeast, the South.
Note: The use of direction is not capitalized.
For example: Traveling northeast of the city is the route to Connecticut. He was going south on his vacation.
But: He was going to the South on his vacation.
Capitalize political, social, athletic, and other organizations and associations and their members.
For example: Democratic Party, Democrats, Sierra Club, Audubon Society, New York Yankees, New York Philharmonic Orchestra.
Capitalize races, nationalities, and their languages.
For example: Native American, French, Spanish.
Note: blacks and whites are lower case.
Capitalize religions, their followers, and terms for the sacred.
For example: Catholicism, Catholics, Judaism, Jews, Islam, Moslems or Muslims, God, the Bible, the Koran.
Note: biblical is lower case, and "the" is not capitalized.
Capitalize common nouns used as essential parts of proper nouns.
For example: street, avenue, park, river, lake, ocean, county, company, college and memorial are capitalized when part of proper nouns like Hudson Street, Park Avenue, Central Park, Hudson River, Lake Louise, Atlantic Ocean, Suffolk County, Ford Motor Company, Union College, Lincoln Memorial.
Capitalize most words in titles and subtitles of works.
For example: "To His Coy Mistress" (Poem), Slaughterhouse-Five (Book), Leaving Las Vegas (Movie), Fahrenheit 9/11 (Movie), "Once More to the Lake" (Essay).