Stripping and peeling off old wallpaper in preparation for painting is only half the battle. Once the paper has been removed, you've got another day or two of work ahead of you to get the walls in tiptop shape before rolling on the paint. Without taking a few extra steps, every blemish in the drywall will be noticeable and the paint will not adhere well to the drywall. Eventually, it will flake or crackle.
Spread drop cloths below the wall to protect the flooring and set up a stepladder near one side of the wall. Wear rubber gloves to protect your hands and make a mixture of hot water and TSP in a large bucket. Add 2 to 4 tablespoons of TSP per gallon of water and stir until it has dissolved. Fill another bucket with clean, warm water to use for rinsing.
Dip a tile sponge into the TSP mixture. Take a second sponge and dip it into the bucket of clean water. Squeeze out excess liquid. Lay the sponges on the stepladder's tray.
Climb the stepladder to begin scrubbing a small area of the wall starting at a top corner with the TSP-soaked sponge to loosen any wallpaper adhesive residue. Wipe down the same area to remove the TSP and residues with the clean-water sponge. Descend the ladder to rinse your sponge often in the clean water. Wipe the area dry with a clean rag. Work your way across the wall using the same technique, accessing the lower wall from floor level. Empty and refill the bucket of clean water often.
Wait a minimum of 24 hours to give the wall time to dry. Examine the wall and look for any defects, cracks or areas that may have been damaged during the wallpaper removal process. Apply joint compound with a putty knife to repair the areas. Allow the compound to thoroughly dry.
Put on a dust mask and sand down the repaired areas with 120-grit sandpaper. Dampen a clean rag and wipe down the entire wall to remove the dust. Put painter's tape on all trim molding, along the edges of adjoining walls and ceiling and other areas you don't want the primer or paint to come in contact with.
Pour a portion of the primer into a paint tray. Apply the primer around the edges or the wall and around the trim molding with a cut-in brush, which has an angled edge and tapered bristles. Use a roller to apply the primer to the rest of the wall. Allow the primer to dry.
Apply the latex paint using a similar technique -- cut in around the edges with a cut-in brush and use a roller for the rest of the wall. Allow the wall to dry and then apply a second coat. When dry, carefully remove the painter's tape.