Remove the material that covers the wood framing, such as the drywall or tiles. If paneling remains on the ceiling once you remove the visible ceiling coverings, pry the nails out with the claw of a hammer and take the panels down.
Measure the length of each joist that runs across the ceiling. Measure the width of one joist from the top, where it sits against the ceiling, to the bottom, which hangs into the room. Ceiling joists commonly measure 6 or 8 inches wide.
Add the number of inches by which you would like to lower the ceiling to the width of the ceiling joist, and get wood boards in this size. If you have 8-inch joists, for instance, and want to lower a ceiling by 4 inches, get 12-inch-wide boards.
Cut the new wood boards down to the same length as the joists in the ceiling with a circular saw. Make the same number of joists as those already installed in the ceiling.
Hang the new joists that you cut for the ceiling as near to the old joists as possible; make sure that the new joists line up with a wall stud. Attach the new joists to the studs with joist hangers.
Put the paneling back over the new joists or install new drywall panels. Cover the ceiling with any type of covering that you want.