Want to visually increase ceiling height? Use of lighter colors on your walls and ceilings give the illusion of more space. Darker floors anchor the room and encourage your eye to travel upward to the lighter colors. Use vertically striped wallpaper (or paint vertical stripes on your wall) will also give the illusion of a higher ceiling. Crown moldings add architectural interest and will also draw your attention upwards.
Another way to visually increase the height of your ceiling is to hang your draperies close to the ceiling, rather than overtop or just above the window frame. Draping the fabric from the ceiling to the floor and possibly even allowing them to puddle slightly on the floor will add both height and drama to your space.