1) When the colon is used to introduce a complete sentence, the first word of that sentence should be capitalized.
- The announcement caught John by surprise: Fans who are standing on the field will be arrested.
2) But when the colon is used to introduce a word, phrase or clause that is not a complete sentence, the first word following the colon should not be capitalized.
- John knew what he had to do when he saw the police: remain calm.
3) Use a colon to introduce a two-sentence (or longer) quotation. Using a comma instead of a colon is incorrect.
- JFK said: "Ask not what your country can do for you. Ask what you can do for your country."
4) Use a colon to introduce a list of items.
- When choosing a computer, consider these three factors: speed, memory and cost.
5) A colon is unnecessary if you are introducing a short list without the words "the following."
- The voters elected Jones, Smith and Marzone.