Sand the area that is chipping or cracking using fine-grain sandpaper. This smooths down the plaster and removes any sharp areas and roughness.
Vacuum the wall to eliminate dust caused by the sanding.
Coat the end of a triangular trowel with a 2-inch dollop of plaster wall spackle.
Press the spackle into the chipped or cracked area of the wall, then scrape the trowel against the wall to fill in the area.
Coat the end of the trowel with a 1-inch dollop of plaster wall spackle.
Slide the spackle over the same area, keeping the trowel 1/8 to 1/4 inch above the wall as you slide. This will blend the spackle into the wall texture.
Repeat to repair any remaining chips or cracks in the wall. Allow the spackle to air-dry for eight hours.
Sand the spackle lightly with fine-grain sandpaper to refine the textured blend and to make the wall look the most congruent that you can. Vacuum the wall as before.
Paint the wall using latex wall paint to match the rest of the wall.