"The tendency is to put too much paint on and it dries with a blob sticking up above the surrounding paint. Less paint is always preferred. "---BC

Well, I grew up in the age of painting where the object was to prep the hole ( read featheredge it ) put enough paint that it would dry above the final surface determined by the paint already there... and use elbow grease and the proper fine abrasives with good backing (read sanding block,perhaps a hard rubber squeegy) to take the extra down to that original line going in alternating diagonal strokes with the longitudinal axis of the sandpaper holder held steady and in line with ( some relationship to the curve whose name I can not come up with this early in the morning ).