DESIGN SCRAPBOOK - Harry Potter set decorator Stephenie McMillan obituary

It was Stephenie who organised the thousand-plus chairs into mountains in the Room of Requirement at Harry's school, Hogwarts, and who over a period of three months supervised the makeover of the Great Hall set for the Hogwarts Yule Ball. As she once explained: "The key to set decoration is noticing the little things. You learn through observation. Look around and see what is in a person's room. I always look to see what books people have sitting behind them in interviews. It's the details." (Craig, 2013).

http://www.theguardian.com/film/2013/aug/27/stephenie-mcmillan