Choose a semi-gloss or high-gloss paint, or a metallic paint, for your ceiling. The reflection on the surfaces of these paints works in the same way that mirrors do to create distance. This makes the space below seem taller and, thus, the ceiling seems farther away.
Paint the walls and ceiling the same color and the trim below the ceiling a different, bold color that contrasts sharply with the wall and ceiling color. As your eyes travel up the wall, they will stop abruptly at the change in shade, rather than continuing to the ceiling. This causes the ceiling, which is difficult to distinguish from the walls, to recede and look higher.
Extend the wall color onto the ceiling. Create a border several inches wide around the perimeter of the ceiling and paint it the same shade as the walls, leaving the center the original ceiling color. This makes the walls look taller and, therefore, the ceiling appears farther away.