Cover the daybed with a daybed cover or futon cover, which gives it a tailored look like a couch. Avoid using coverlets or other fabric items that hang down over the front and are associated with beds.
Add pillows for back support, important for making the daybed look and feel like a couch. Without enough pillows, the twin-size mattress on the frame will be apparent. You can use a wedge-shaped cushion with a foam back, but be careful when selecting your purchase because some of these are not very comfortable. Another solution is placing four king-size pillows or two body pillows along the back. Cover them with pillow shams that fit into your decor.
Add several throw pillows so people can adjust seating for their own comfort. Extra pillows are needed for anyone who wants to sit far enough forward to have his feet on the floor, for instance. Other people may feel more comfortable sitting cross-legged.
Place bolster pillows at the sides so people have something comfortable to rest their arms on.
Place a coffee table in front to reinforce the illusion that the daybed is a couch and not a bed.