Sand the finish if it is not extremely thick. Use a sanding pole with rough grit sandpaper. A hand sander also is recommended. Before beginning the project, remove all furniture and other items from the room. Close all air vents and turn off the heating or cooling system. Remember to wear protective gear, such as eye goggles and a dust mask. An extreme amount of dust will be created. Ensure you have plenty of sandpaper on hand. An extra set of helping hands will help this project move quickly.
Cover the wall with wallpaper liner to disguise the texture, if sanding the finish completely smooth is not an option. The liner is installed similar to wallpaper and hung in sheets. Skim over connecting edges with joint compound and paint the wallpaper liner with latex paint.
Skim and fill in the texture if the texture is extremely light. Use a drywall trowel and put a small amount of joint compound on the flat edge. Hold the trowel with one side against the surface and skim the trowel across the texture. The joint compound will fill in any holes and crevices created by the venetian stucco texture. Allow to dry and sand with medium grit sandpaper. Continue to skim the surface and sand until a smooth wall is created. You may have to follow the technique three to five times. Always wipe away all drywall dust with a damp cloth between layers or the plaster will not adhere well.