Select a rug that is large enough to rest under your entire couch as well as any other side chairs or tables that you plan to place directly on it. If the rug is too small compared with the couch, it can make the room clash.
Set up your rug in either the center of the room or off to the side to create a private area. While you can turn the rug on an angle in large rooms, it’s generally a better idea to leave angled pieces to the furniture and keep the rug in line with the walls of the room.
Arrange your couch to sit along either edge of the rug with all four feet on the rug. If you want to set the couch at an angle, still be sure the couch has all four feet touching the rug to make it look proportional to the rug.
Add any additional pieces to the rug such as chairs, a coffee table, or end tables with the couch, keeping them on the rug, but don’t overcrowd the area. You’ll also need to be sure that the couch and these other furniture pieces work well together as far as size goes so as not to dwarf one another.