All too often, colons are misused in writing. This punctuation mark is meant to signal readers that what follows is a proof or explanation of what came before it. For example, the following sentence requires a colon rather than a comma:
Laura wanted to move for Los Angeles for three reasons: the great weather; the laid-back lifestyle; and all of the fun things to do there.
What appears after the colon explains why Laura wanted to move to Los Angeles. Note that semicolons are used to separate each reason after the colon.
The portion of the sentence appearing before the colon, however, must be a complete sentence. Of course, Laura wanted to move for Los Angeles for three reasons, is a complete sentence. If it were not a complete sentence, no colon is needed:
Laura wanted to move for Los Angeles because of the great weather, the laid-back lifestyle, and all of the fun things to do there.
Of course, Laura wanted to move for Los Angeles because of is not a complete sentence. Also note that commas rather than semicolons are used to separate each reason given.
An exception is introducing block quotes and bulleted lists, which often appear in newspapers, magazines and on website articles. To wit:
Laura wanted to move for Los Angeles for:
• The great weather
• The laid-back lifestyle
• All of the fun things to do there
Note that in a bulleted list, semicolons, commas and periods are not needed at the end of each bulleted item. The exception is if each bulleted point is a complete sentence; then a period is needed.
My name is Rob Bignell. I’m an affordable, professional editor who runs Inventing Reality Editing Service, which meets the manuscript needs of writers both new and published. I also offer a variety of self-publishing services. During the past decade, I’ve helped more than 300 novelists and nonfiction authors obtain their publishing dreams at reasonable prices. I’m also the author of the 7 Minutes a Day… writing guidebooks, four nonfiction hiking guidebook series, and the literary novel Windmill. Several of my short stories in the literary and science fiction genres also have been published.