Plan your route. Take a moment to clear a path from the couch to the door, if taking the furniture outside, or to another room. It's much easier and safer to carry a couch if you don't have to stop to move obstacles out of the way.
Bend at the knees on the short end of the couch while your helper does likewise at the other. Grab the couch from underneath, not by the legs, if your couch has them. Couch legs can potentially break off, causing the furniture to pivot unexpectedly and possibly causing injury.
Stand up to raise the couch, keeping your arms straight and locked at the elbows.
Turn the couch in your hands at an angle to get the furniture through a door. It may be necessary to turn the couch so that the back points toward the floor so you can move the narrowest end of the couch through a door. Unscrew legs from the couch if they can be removed so the legs cannot get caught in the door frame.
Turn the couch upright and lower to the floor in the new room, carry to the curb for disposal, or lift up to slide onto the back of a moving van.
Cover the couch with a plastic tarp or dropcloth to protect the upholstery if moving it in a truck.