Rule:
1) Capitalize the first word in a sentence.
2) Capitalize proper nouns.
3) Capitalize geographic names.
4) Capitalize the pronoun I.
5) Capitalize the names of days and months.
6) Capitalize the names of national, religious, and local holidays.
7) Capitalize proper adjectives.
8) Capitalize words used as names.
9) Capitalize titles used as names.
10) Capitalize the first word in the greeting or closing of a letter.
11) Capitalize the first, last and all the main words in the title of a book, movie, song, magazine, play, newspaper, or television show.
12) Capitalize the names of organizations, associations, or teams and their members.
13) Capitalize the names of businesses and the official names of their products.
14) Capitalize historical events, documents, and periods of time.
15) Capitalize the initials or abbreviations that stand for names and also abbreviations of titles and organizations.
Example:
1) Another dog ran by the boy.
2) Billy, Empire State Building, Miami Dolphins
3) Indian Ocean, Hawaii, New York City
4) He asked if I wanted to read next.
5) Tuesday, October
6) Memorial Day, Easter, Founder's Day
7) French, Chinese
8) Do you need help, Mother?
9) General Bradshaw, Mrs. Key, Chief Dann
10) Dear friends, Yours truly
11) Harry Potter and the Sorcerer's Stone
"The National Anthem"
12) American Red Cross, Parent-Teacher Association, Rolling Arsenal of Derby
13) McDonald's hamburgers, Colgate toothpaste
14) Boston Tea Party, Declaration of Independence, Stone Age
15) Richard T. Smith, M.D. (Doctor of Medicine), PTA (Parent-Teacher Association)