take a leaf out of somebody's book
take a leaf out of (one's) book
To do something in the way someone else would do it; to behave or act like someone else. I think I'm going to take a leaf out of your book and start going for a run first thing in the morning.
take a leaf out of somebody’s ˈbookfollow somebody’s example because you admire them and their way of doing something: If you’re having difficulty with the children, take a leaf out of Sandra’s book. She knows how to control them.
Leaf is an old word for a page.