What have we learned from Lyddie in the book?
Different readers are going to learn different things from Lyddie's character. Based on the question, it seems that the answer is completely open ended, and you can state whatever you believe that Lyddie taught you. Be sure to back up your claims with explanations about why you feel that way.
I do believe that no matter who the reader is though, that readers learn about the value of family through Lyddie's character. Early in the novel, she is separated from her family because of the debt that her father left the family with. Canceling out that debt is her number one goal, because without the financial debt, Lyddie's family can return together to the farm.
I also believe that Lyddie (the person) also teaches readers about hard work and determination. Lyddie is anything but lazy. She is willing to work herself into the ground in order to be successful. I think a lot of people could stand to learn that lesson. The things in life that are worth pursing take a lot of work. Lyddie is constantly being given obstacle after obstacle, but her determination to see things through allows her to continually be successful.