I literally put a black skirt from the Gap on my khaki sofa so that it would be a black background.

and the only lighting I used was from the windows. There was a sofa directly behind the sofa (that is why her fingers are so bright in the one of her on her back) and then there was a window to the left of the sofa. The arms on that sofa are very low, so most of the light that fell on her came from the left.