Remove the headboard and/or foot board from the bed.
Move the bed so that it is positioned horizontally against a wall. The wall will serve as the back of the sofa. The best location for a day bed is in the center of a wall, with space on either side.
Stick several self-adhesive Velcro strips along the wall that the bed is touching. Place the strips about 6 inches above the bed and spaced about 6 to 8 inches apart.
Stick the matching backs of the self-adhesive Velcro strips onto the backs of several medium-sized pillows.
Line the pillows along the wall and match the Velcro strips on the back of the pillows to those on the wall. This will create a kind of backboard for the sofa that can be easily removed at night.
Place a comforter and sleeping pillows in a storage basket or box and set the box in a discreet location near the couch. At night, these items can be used to turn the sofa back into a bed.
Place a thick throw over the bed to use as a surface for sitting. Keep the throw on the bed during the day. At night, remove the throw and the decorative pillows and place them in the storage basket or box.