Don't use a colon to separate sentence elements that belong together, such as an action verb from its objects or a linking verb from its complements. The university sent us catalogs, maps, housing applications, and transportation information. NOT The university sent us: catalogs, maps, housing applications, and transportation information. The four things I want are success in business, a happy marriage, creative fulfillment, and peace of mind. NOT The four things I want are: success in business, a happy marriage, creative fulfillment, and peace of mind.