If you're painting an entire room, paint the ceiling first. That way you can cover paint splatters on walls later.
Cover furnishings and flooring with drop cloths to protect surfaces from paint splatters. Even better, relocate furnishings to another area of the house so you can move around the room unencumbered.
Protect the top of the wall or crown molding with painter's tape unless you plan to paint the wall. In this case, you can overlap the wall slightly and paint over it later. Protect the edges of light-fixture rims or canopies that touch the ceiling using painter's tape, or unscrew and drop the canopy slightly away from the ceiling so you can paint near the opening. When you finish painting, return the canopy to its original position. Protect ceiling-fan blades with plastic or newspaper secured with tape.
Shine a light on the ceiling so you can spy imperfections and fill with spackling compound. Let filler dry and sand smooth. If your room has a popcorn ceiling texture that you'd like to remove, start here for how-to instructions, and remember that you'll first need to check for the presence of asbestos.
How to Paint a Popcorn-Textured Ceiling
If you plan to keep the popcorn texture on your ceiling, use the flat tip of a screwdriver to knock off a thin band of texture where the ceiling meets the wall. This will allow you to achieve a cleaner edge when you paint your ceiling's edges, whether you opt to use painter's tape or just a steady hand.
When it's time to roll on the top coat, use a segmented foam roller or a thick-nap (3/4-inch) roller. To prevent texture from oversaturating and peeling away, apply paint with a light hand, and try not to roll back over an area once you've applied the paint. Let the ceiling dry thoroughly before applying a second coat.
Whether they're spots from grease, smoke, or a leaky roof, cover ceiling stains first with a stain-blocking primer so the color won't leach through the finish coat.
Make sure you have a sturdy, safe stepladder that remains steady as you reach for the ceiling.
When selecting paint for your ceiling, opt for flat, matte, or eggshell finishes, which tend to hide imperfections.
Get a helper or two for cutting in and rolling on paint to make the job go faster and to ensure that you paint into wet edges (which helps minimize lap marks).
Use a 2- or 2-1/2-inch angled brush to cut in a 3- to 4-inch-wide band of paint around the edges of the ceiling. This allows you to roll on paint afterward without getting too close to the walls and accidentally getting paint on them from the roller. Start in one corner of the ceiling and paint out in both directions several feet before applying paint to this first section of ceiling while the edge is still wet. Or if you have a helper cutting in, immediately follow the helper and apply paint to the ceiling with a roller.
Use a 9-inch roller with a 1/2-inch nap to hold a generous quantity of paint. Add an extension handle so you can roll paint on the ceiling without getting on a ladder. As you roll, apply only moderate pressure so paint doesn't splatter. Roll the paint in small sections, using a back-and-forth motion, starting in one corner of the room and working your way across. Don't roll the paint on in zigzag or W-shape patterns.
As you work your way across the ceiling, position the roller a foot away from the wet edge and roll the next section into the wet edge, overlapping it slightly. Keep rolling until the entire ceiling is covered. Let dry and apply a second coat, cutting in as noted before and then rolling on another coat perpendicular to the first coat for best coverage.