In baseball, a leadoff batter is the table setter. Someone who gets on base, gets the crowd excited, and gets the pitcher nervous. A leadoff batter sets the tone and often foretells how the game is going to go.
The same is true for writing. A strong lead draws a reader in and keeps the reader reading.
Here are some samples from well-known books:
From Harry Potter and the Sorcerer's Stone by J.K. Rowling:
"Mr. and Mrs. Dursley, of number four, Privet Drive, were proud to say that they were perfectly normal, thank you very much. They were the last people you'd expect to be involved with anything strange or mysterious, because they just didn't hold with such nonsense."
From Jeanne DuPrau's, The City of Ember:
"When the City of Ember was just built and not yet inhabited, the chief builder and the assistant builder both of them weary, sat down to speak of the future.
'They must not leave the city for at least two hundred years,' said the chief builder. 'Or perhaps two hundred and twenty.'
'Is that long enough?' asked his assistant.
'It should be. We can't know for sure.'"
From Kate DiCamillo's, The Tale of Despereaux:
"This story begins within the walls of a castle, with the birth of a mouse. A small mouse. The last mouse born to his parents and the only one of his litter to be born alive.
'Where are my babies?' said the exhausted mother when the ordeal was through. 'Show to me my babies.'
The father mouse held the one small mouse up high.
'There is only this one,' he said. 'The others are dead.'
'Mon dieu, just the one mouse baby?'
'Just the one. Will you name him?'
'All of that work of nothing,' said the mother. She sighed. 'It is so sad. It is such the disappointment.'"
Click here for some student examples of writing leads from 2007. They practiced by writing interesting leads and poor leads.