In nature, mice usually eat grains, eventually insects. However, inside an apartment, they won’t refuse anything sweet or fatty. In my experience, the most effective bait is peanut butter (only a tiny amount is enough). If you don’t have it at home you can try chocolate, soft cheese, bacon, and sunflower seed as well. There are attractant gels available in the stores but I’ve never tried them because I always get great results with the foods I mentioned earlier.