To get a great paint job in any home, you need to spend a good amount of time on prep work. Wall mud available at any paint store or home center is the best for patching holes or gashes in drywall, but for trim, you might want to go by the auto parts store and pick up some Bondo.

Bondo is more durable, and you’ll know exactly when to stop sanding because all you’ll see is the filled nick or hole. Then the color of the hardener you put in the bondo shows you where the filling needs to be covered by the paint... another big advantage over ordinary spackling fillers.

You’ll need to experiment a little bit with the hardener to learn just how much to add so the Bondo doesn’t dry too fast, but it’s advantages make the short learning curve well worth it.

Once it's dry, sand the Bondo with a 100-grade sandpaper. Then you can get a smooth finish with a couple of wipes with a 150-grade paper.