How do you know which room to renovate?

I was supposed to renovate one room and went in to find the whole house open to me, so I just picked one and got started. She only told me she liked green and pipe organs and hated Storybook style, so I just plopped down a pipe organ and painted the room green, then changed all the fixtures to be green. She was thrilled with that. It looked pretty gross, but whatever.