Paint the ceiling with a textured paint. Select one with the level of coarseness you desire and one labeled for ceiling applications. You may have to mix in water or a powder, depending on the paint. Apply to the ceiling per user instructions, using a roller covered with a stipple roller cover or a roller specifically labeled for textured paint.
Paint a section of the ceiling as normal using a smooth paint. Before the paint dries and while it is still visibly wet, go over the paint with a comb or brush. You can create any pattern you want, including straight lines, checkerboard and waves. After lifting up the comb or brush to drag it across the next row, wipe the paint off of it with a rag.
Dip a lint-free rag in paint, wring it out, roll it up like a ball and roll it onto the ceiling. Experiment with different patterns and types of rags, such as cheesecloth or burlap, to find a desired texture.
Dip a sponge in paint, wring it out and dab it onto the ceiling. You can also dab the end of the sponge on the ceiling and twist for a different effect. Use either a natural or synthetic sponge, but in general, a synthetic sponge creates a more uniform pattern than a natural sponge.