When you live in the country or in an area that isn't clear and mowed, mice are a fact of life. Mouse traps work with consistent use, but to prevent mice from coming into the house, make sure everything nearby is mowed and clean. Keep any kind of seed, pet food and garbage away from the house. Trim bushes and other growth completely away from the house. Mice can come through very small holes or cracks, so check around your foundation and where the floors meet the walls especially. This may be a no brainer, but keep doors closed and make sure screen or storm doors fit very snugly.
Don't store dry goods in plastic, but put it all into glass containers with good lids. Don't keep your home too cool when it's hot out or too warm when it's cold out. Mice look for comfort and food, so do your best to not provide that for them.