Older houses and those renovated into apartments may not have actual closets, but can include some other funny spaces that can be converted. Occasionally, these turn out to have angled walls (or ceilings, depending on your point of view), which can be turned into decent clothing storage areas, especially when you consider that most of the space above a shelf-and-rod system is wasted. As long as there's enough height to hang clothes straight, and width enough to fit any jacket with padded shoulders, there's a place for a closet rod.
Measure the length of your longest piece of clothing, using the tape measure. Add 8 to 12 inches, this is the necessary height for the bar. Mark this spot on the wall. Find your widest piece of clothing and measure across it, and add enough width to compensate for the upward slope; this determines the open distance from the flat wall, and the point directly above where you'll install the rod. Mark that with a pencil, as well.
Hold the bar up against the mark on the ceiling; you might even hang something long or wide from it, just to be sure. Find the right spot, and draw lines at either end of the rod.
Set a bracket against the wall and mark inside its screw holes. Do this for the other end of the rod, also.
Insert the screw anchors into the wall, using a screwdriver, in the place where the hang bar supports will be.
Install the hang bar supports, using the hardware included with the screw anchors and a screwdriver.
Attach the rod by inserting it into its brackets.
Knock on the space where you want to hang the rod. Hearing a solid thud means that it's a relatively solid base.
Test the rod for weight a little bit at a time; you have to stay within the capacity of the screw anchors.