Prepare the area. Lay a drop cloth on the floor, and use masking tape to protect fixtures and fittings such as light switches, plug sockets and glass.
Repair any damage in the wall using spackling paste. First, roughen the surface with a fine-grain sandpaper, and use a spatula to smooth over the spackling. Leave the compound to dry for 20 minutes, or follow the guidelines on the packaging.
Sand the spackled area until it is smooth and even with the wall. Wipe off the dust with a damp cloth.
Apply a coat of primer. This will create an even surface for the paint to adhere to the wall, and will cover irregularities and patchy areas. Allow the primer to dry completely.
Paint the area with a roller. Blend in the edges of the new coat of paint with light strokes, lifting the roller away from the surface of the wall as it nears the original coat. The paint should dry with an even surface.