With a point-type laser level, you can lay out your ceiling box and light fixture locations on the floor, where it's easy to measure, and then use the laser to transfer them to the ceiling. This technique is especially useful for vaulted or sloped ceilings, where locating light fixtures would require a plumb bob.

Start by marking the light fixture locations on the floor with masking tape. Then elevate the laser and line up the downward pointing beam with the center of the fixture. Now you can mark where the upward pointing beam hits the ceiling.