Prepare the wall properly. Patch any defects with joint compound and sand it smooth. Wash over the entire wall with a warm, soapy water solution or add one part trisodium phosphate to four parts water to remove stains and grease or oil. Air-dry the wall before sanding slightly to scuff the surface and encourage adhesion.
Clear all furnishings from the room, whether you're painting the wall or the ceiling, or arrange them in the middle of the room and work around them. Cover the floor and anything that remains in the room with plastic sheeting. Tape off areas you don't want painted, such as any wood trim.
Pour a gallon of the textured paint into a clean 5-gallon bucket. Stir the paint thoroughly to ensure the pigment is evenly mixed.
Use a small paintbrush to apply the paint near the edges and corners, whether applying the paint to the ceiling or the walls. Work out a few inches from doors, windows, adjacent walls, light fixtures or any other permanent object if you can't paint right up to it with a roller. This step is called cutting in and is essential for proper coverage as well as preventing the paint from spilling on a surface that you don't want covered.
Insert a 9-inch bucket grid into the paint bucket. Use a smaller grid for smaller buckets. Dip the looped roller down into the paint, then roll it down the grid -- without touching the paint in the bucket -- several times. This will remove excess paint from the roller.
Starting at the far corner of a ceiling or the at the top of a wall, in the corner, apply the paint. Make long, even strokes in a zigzag pattern -- a W- or M-shape is ideal. Fill in around the initial strokes with subsequent strokes, covering a 3- or 4-foot-square area at one time. If you work in larger areas you may apply the paint unevenly, or it may dry between strokes, resulting in a sloppy appearance.
Dip the looped roller back into the paint as necessary to constantly supply a fresh, even coat of paint. Roll over the grid with each paint load before applying. Working quickly, moving down the wall or across the ceiling in rows before proceeding to the next row. Fast application and zigzagging strokes ensures a more even, proper application.
Apply a second coat, if desired, only after the first coat is completely dry. A second coat -- according to Behr, the paint manufacturer -- helps the paint to look more consistent.
Follow with a topcoat of regular paint to protect the textured coats. Let the textured coats dry at least 24 hours before applying the topcoat.