An attractive picture that helps the reader feel relaxed, a clear headline, and a chance to provide feedback. 

An opening that provides the information the reader wants. A chance for the reader to complete a poll about the information to receive a reward.

The main information the reader wants first, then something to engage the reader to learn more. 

An opening that engages the reader's attention enough that they want to read more. Useful, surprising or engaging information that rewards their curiosity.