Remove all trash, logs, boards, stones, bricks and other objects from around the structure.
Keep grass closely mowed near the structure. Prune bushes and overhanging tree branches away from the structure. Tree branches can give scorpions a path to the roof.
Store garbage containers in a frame that keeps them above ground level, if possible.
Never bring firewood inside the structure unless it is placed directly on the fire.
Install weather-stripping around loose-fitting doors and windows. If you can see light around the edges that is an entry point.
Plug weep holes in stone or brick veneer structures with aluminum window screen, it blocks access but allows the house to still breathe & sweat as needed.
Use sealant around roof eaves, pipes, and any other cracks into the structure.
Keep window screens in good repair & make sure they fit tightly in the window frame.