After thoroughly examining your assignment, now it's time to do some initial research into the different generations, so that you can begin to focus on which one you want to argue is the greatest generation.
As you read, remember that it is up to you to decide on the definition of 'great.' How are you going to define the greatest generation? Here are some aspects to consider (this is not a complete list):
The book below, American Generations: Who They Are and How They Live, provides a nice overview of the six living American generations in "The Generations," and then each chapter after that compares the generations on a different topic, such as Attitudes, Education, Income, Time Use, etc. Consider which aspects you could use to support your argument for a generation's greatness. Take notes for later.