Avoid rolling the rug in the opposite direction it was originally rolled. For instance, if the rug was originally rolled so that the right side was rolled inwards, do not roll the rug so that the right side is on the outside.
Set a flat heavy object, such as furniture, on the area of the rug that needs to be flattened. Allow the furniture to sit on the rug for a couple of days.
Steam- iron the rug if it it still not laying flat. Place the iron's temperature setting on "Wool." Run the iron over the area that is not laying flat. When ironing, be sure to iron in the direction of the carpet pile. To determine the pile direction, run your hands across the carpet toward the fringes. Iron in the direction that feels smooth, not the direction that feels rough. When finished ironing, smooth down the edges with your hands until the rug lays flat.