Measure the height and width of the storage area you're covering with curtains. If you're hanging curtains in the door frame of a closet, measure the width between the frame and the distance from the inside top of the frame to the floor. If you're covering an alcove or bookcase, measure the distance between the walls on either side and from the ceiling to the floor.
Select curtain panels that are 1 1/2 times to double the width of the door or area between the walls so you get a full look when you hang the curtain. The panels shouldn't be longer than the distance from the floor to the top of the door or the ceiling. If they are, hem them to the correct length.
Slide the curtain panels onto a tension curtain rod. A tension rod doesn't require screws or any hardware, making it the the simplest type to use.
Hang the curtain rod in the door frame between the walls of the alcove or in front of the bookcase.