Colons are not used to introduce lists omissions appostives long quotations

Colons are not used to introduce lists.  

Colons denote "that is to say" or "here's what I mean."

They make sentences’ first parts not important rather the sentence’s second part contains the important information.

Here are some of the rules you could use for colons:

*Colons are uses upon introducing items.
*Do not use capital letters after a colon except if it’s a proper noun.
*Do not use colons after a verb or preposition.
*For independent clauses, especially when the second sentence explains the paragraph’s meaning, the use of colon is preferred.
*After a colon: capitalize the first letter of the first word if it is a complete quotation.