The building I worked in had traps outside to stop the mice from even getting in. Curious little black boxes lined right up against the foundation. They had a hole pointed along the wall, but I have no idea what was inside.
If you can, inspect for places they might come in. It can be difficult, because they can squeeze through holes the size of a nickle (or some insanely small gap). Stuff steel wool in the hole, then secure with some expanding foam. They won't chew through it.
The placement of the traps is also very important. You need to put them along the walls and such, although I believe most stickies are designed that way anyway.
Good luck!
If you can, inspect for places they might come in. It can be difficult, because they can squeeze through holes the size of a nickle (or some insanely small gap). Stuff steel wool in the hole, then secure with some expanding foam. They won't chew through it.
The placement of the traps is also very important. You need to put them along the walls and such, although I believe most stickies are designed that way anyway.
Good luck!