We trapped over 2 dozen little critters and were still finding them everywhere. I finally called a pest control company and this is what I have learned from them. Mice naturally look to come into a warm home this time of year. If you have a garage, focus a lot of attention there. Remove the food source.
Mice love to eat grass seed.
Many people store this in their garage. If you have some, put it in an airtight container so the mice aren't attracted. Same goes for dog food. Dog food is VERY popular with rodents. If your dog is fed outside, be sure only to feed him when he is hungry and only feed him the amount he will eat at one serving.