You can try patching the holes in your plaster walls yourself if you want to save money and improve the look of your rooms. Patching plaster is a pretty easy job, as long as you exercise some patience while you are working and choose the right tools for the job. Start with small holes so that you can get the hang of patching before you try your hand at big repairs.
Choose a setting type compound to make your repair. These compounds are water soluble and you can sand them if you make a mistake. Clean your hole of any dirt or grease. Remove loose plaster. Make sure that the plaster you leave on the walls is firmly attached and brush out any dust left over from plaster you remove. Dampen the area you want to patch with water.
The easiest holes to patch are no bigger than two inches and less than half an inch deep. If your hole is deeper than this, fill it half way with joint compound, let the compound dry, and then fill it the rest of the way. If you try to add too much wet compound at once, it won't dry properly, will crack and fall off. If your hole is less than half an inch thick, use drywall finishing tools to make your patch. You can use a flexible broad knife to apply your setting compound to the hole like icing on a cake. After you fill your hole, you can gently wipe down the top with a wet sponge in order to smooth your work.
Allow your setting compound to dry overnight. The following day, check your work. If your plaster looks bumpy, you can sand it down a bit with some sandpaper. If the patch job looks good, go ahead and paint over it so that it matches the rest of your wall.