The reader is asking three questions ’Why is this character here? What is he doing? And why is this happening now?’ Don’t disappoint but deliver the goods. Buying the book is a contract between the writer and the reader. What do they expect? Know this and deliver.
Never give the reader anything they don’t need to know. Only tell them only what they need to know to follow the story, allowing you to save the best for last.
Make the reader wonder what’s going on by putting them in the same position as the character. As long as the character wants something, the reader will want it too. As long as the character is attempting to get something, the reader will wonder whether or not he’s going to succeed. Few things are more intriguing than secrets.