Cover the length of the daybed with a quilt or quilted coverlet. Do not use a comforter or duvet, as this gives the appearance of a bed. Instead, use living room-style blankets to give the daybed a sofa-like appearance. Tuck the blanket snugly around the sides of the daybed mattress.
Line the back of the daybed with three or four large throw pillows, similar to the kind of pillows you would see on the back of a sofa. These pillows will provide the comfortable base for a person to lean back against the daybed, which often as metal scrolling and open spaces that are not ideal for a comfortable sitting.
Add smaller throw pillows of different colors and designs against the large throw pillows. Try to fill in about 3 inches of width from the large throw pillows. A daybed is wide. Therefore, by filling in some of that width with extra throw pillows, you will turn the daybed into more similar dimensions of a sofa.