How to Paint Walls
If the ceiling needs to be painted as well as the walls, paint the ceiling before you paint the walls. Any paint that falls on the walls while the ceiling is being painted can be cleaned off or covered over by the wall paint. Be sure you have adequate ventilation in the room before beginning, especially if you are working with oil-based paint.
What is Being Painted Over
If you are painting over a previously painted wall, this will be simple in comparison to painting over other surfaces, such as wood paneling, wallpaper, or badly stained drywall. In the case of simple painted drywall, you can use a latex primer and paint, which are easier because you can rinse the brushes off with water. On some surfaces which have colors which can bleed through the paint, such as wallpaper and drywall, or stains which can discolor the new paint coat such as some water stains, and stains resulting from smoke or fire, or stains which have a strong odor such as pet stains, you will need an oil-based primer. Over oil-based stains, such as greasy food stains, some water stains, and such surfaces as glossy paint, cinder block, wood paneling or drywall, a latex, water-based primer and paint should be used.
Remove Wall Hardware
Remove all wall hardware, such as switch plates and outlet covers, from the walls and save them with the screws in a safe place until after the painting is done. Mask the remaining hole with the electrical parts inside with masking tape or painter's tape. Remove all pictures, posters, and other wall hangings from the walls. Move all furniture from the walls toward the center of the room or out of the room completely. Leave room in front of the walls to walk while painting. Whatever won't move from off the walls, such as cabinets, mask with wide masking tape or blue painter's tape. If the ceiling is not being painted at this time, mask it along the edges, as well as any trim, unless they are being painted along with the walls. Similarly, the baseboard and window and door trim should be masked unless they are being painted along with the walls. You may want to remove any doors also, or mask them with tape. In other words, get everything that you don't want to be painted protected from paint by either removing them from the walls or masking them with tape. Whatever is left in the room, such as the furniture and wall hangings, place drop cloths or canvas tarps over these and the floor and seal the edges with painter's tape. Use a short nap roller for painting walls.
Prepare the Surface
Clean off any stains with the appropriate cleanser. Use water-based cleaners on ordinary water-soluble stains such as food and grease. On tougher stains that need a solvent to clean them off, use the appropriate solvent to remove them unless doing so will damage the underlying wall. Use wood filler or drywall mud to fill any holes or depressions in the surface. Scrape or sand any raised defects in the wall such as peeling paint or wallpaper, or bumps in the paint coat. When scraping or sanding, protect yourself from hazardous lead paint exposure by wearing an approved face mask and protective clothing, and being careful to remove all dust and paint debris from the walls and dispose of it in the EPA-approved manner. After all the wall repairs are done, sand the walls to roughen them for the primer, wipe off the sawdust, then clean the walls with trisodium phosphate or a TSP substitute and water using a sponge, and allow to dry.
Painting a Wall
The first coat of paint will be the primer, then the paint on the top following after. Allow each coat of paint to dry the recommended time on the label before applying another coat of primer or paint. Cut in the wall by painting around the edge of the wall with a 2-inch or 2 ½" paintbrush, covering in from the edge in a 3-inch wide stripe, painting from the walls toward the center of the wall enough to cover the areas that the paint roller will not be able to cover due to its cylindrical shape. Then use the paint roller first in an upper corner of the wall to make a "W" shape in a square area of the wall about 3 feet square. Fill in the "W" with the paint roller. Feather the edges of the painted square area by applying the paint with a lighter touch with the paint roller. Move downward to repeat with another similar square area, painting adjacent square areas all the way down to the baseboard. Next, after this column is painted, start painting another square area near the ceiling next to the last column, and continue painting columns in the same way until the wall is completed. Then go on to another wall, cutting in the brush, then painting with the paint roller in the same way. Do the other walls afterward one at a time until the painting is done. Allow to dry the recommended amount of time and then apply the next coat in the same manner until done.
Baseboards and Trim
Use an angled brush to paint the trim and baseboards. You may paint them at the same time as the walls if you want them to have the same color as the walls, or you may paint them with a different color paint. If you use the different color paint, wait until the walls are dry and then mask the edge of the walls against the trim and baseboards with painter's tape before painting the baseboards and trim. After the paint on the baseboards is dry, remove all the masking tape and drop cloths and replace all the wall hardware and art, the doors and the furniture in the room.