Do not forget to account for any supplies that you might have to purchase for painting the room (such as rollers, brushes, painting tape, and drop cloths). Out of dozens of different paint tools out there, you only need two paint brushes and two paint rollers. Generally, for latex- or water-based indoor painting, all that might be needed includes the roller, a roller tray, an extension pole for the roller, a narrow angle brush (two-to-four inches) to cut through or make close-ups between walls and ceilings or trim, a wider brush for areas that are tighter than a roller, jars of paint, and stir sticks. Before starting painting a wall, trim edges with one- to two-inch brushes.
To cut in, draw a line of paint down the walls, about one-inch from the edges. Once you are done painting the section of the wall top-to-bottom, make a single, long roll from the ceiling down to the floor to remove any roller marks. Next, you can proceed by cutting into the painted walls at the edges along the ceiling and around your trim and baseboards. Use a clean paintbrush to paint the edges, approximately three inches out of the corners of the room, around windows and doors, around baseboards, and under the ceiling.
Using your corner paintbrush, begin painting a strip that is 2 inches to 3 inches long down your ceiling, floor/baseboard, molding, and the interior corners where the two walls meet. Use an angle brush or sponge tool to make the cutouts, or paint a 2-inch swath along the edges of your trim and ceiling. Then, using a small, angle-tipped (1-2-inch) paintbrush, complete the trim by carefully painting straight lines around the edges. Using angled, bristle paint brushes, carefully paint a 2 – 3 inch strip down where the ceiling meets the wall, or alongside your walls crown molding.
Use your brush to trim off 2 to 3-inch strips of paint in all corners, along the ceiling, and near molding; this will give the roller a little breathing room to avoid slamming into nearby areas. Hold a smaller one at an angle, like in Step 5, and allow the hairline paint drip down onto the walls to compensate for any imperfections on the molding itself. Start the process of painting your room with the help of a small paintbrush, which you will use to mask off edges (this is known as cutting-in, says Bryan Levy). When you are ready to start painting, remove as much furniture as you can from the room, taking care to protect your floor with a drop cloth or plastic sheet.
First, dry-dust the walls floor-to-ceiling, and wipe down any overly grimy areas with a damp sponge or cloth; paint does not stick well to dirty surfaces (think fingerprints, soot, dust, spiderwebs). Once the walls are dry, pop the primer cans and mix in the primer with the paint brush.