Rub some spackling paste into the hole and spread it over the hole using a putty knife. Allow the paste to dry.
Sand any excess putty away very gently. If there are any visible lumps or edges of the putty that are noticeable, use a circular motion to remove them. Don't over-sand; sand only enough to make sure the putty is flat against the wall.
Paint over the area with a paint shade that matches the wall and a small brush. It will not take a lot of paint to camouflage the area, so use it sparingly. Allow the area to dry for at least an hour.