Unscrew the legs from the bottom of the couch if they are removable to give yourself some extra space when moving the couch. Remove the cushions as well.
Measure both the couch and the height and width of the basement and any doorways to determine how much room you'll have to work with when trying to move the couch.
Ask someone to help you when it's time to move the sofa. This helps reduce the risk of injury, and another person will help prevent damage to the couch or any doorways.
Tilt the couch to get the largest dimension of the couch facing up and down to maximize the free space widthwise when you are turning a corner or going through a door.