What's "put the best face forward" mean?

Native speaker’s answer
Rebecca
"Put your best face forward" is a play on the original idiom, "put your best foot forward." It means that you should behave very well to get someone's approval. Because the story is about Facebook, they could have decided to use "face" instead of "foot." Ex: You have to put your best foot forward when meeting someone important for the first time. Ex: He put his best foot forward after getting a warning from his boss.