Before sanding, round up a shadow light, a wide taping blade and a pencil (not a felt tip pen; it bleeds through paint). Map all wide seam work on ceilings and walls to plan how much to sand each seam ...

"Why am I still getting swirl marks on my workpiece?" It’s not a simple answer, but going through the below steps should get you to the swirl-free finish you are hoping to accomplish. Random orbital ...