Keep bushes and trees at least a foot away from your home to help prevent problems with spiders and other insects. Also keep mature trees trimmed and away from the house, to stop roof rats from accessing the roof or attic of the house.
Make sure you can't see daylight through the bottom of your exterior doors (i.e. front door and garage access door). If so adjust the height of the door threshold and/or add weather striping seals to the door.
Seal off or caulk any holes in or around your home to prevent insect or rodent infestations.