Make sure to place steel wool in any hole area and seal all possible entries. If you have baseboard heat make sure there are no holes behind the baseboard system. Set up mice traps, and I would also suggest getting pest repeller plug in for each room.

Peppermint oil, cayenne pepper, pepper and cloves. Mice are said to hate the smell of these. Lightly soak some cotton balls in oils from one or more of these foods and leave the cotton balls in places where you've had problems with mice. Another option is to make cheesecloth sachets from dry cayenne, mint, and whole cloves and leave them in places where mice tend to hide, such as under beds and corners.

Ammonia smells like the urine of a possible predators. Fill caps from plastic bottles with ammonia and leave them out anywhere mice might be tempted to enter, such the pantry or under the sink - just be sure to place them out of reach of pets and children.