Toenails should be clipped every two weeks. The proper way to cut a toenail is to clip straight across. Toenail length should not extend past the end of toe. You can check this by running your finger across the edge. After being cut the nail should be filed smooth. Never round the corners or trim them too short because they can begin to grow into the skin and cause an ingrown toenails, which can become red, inflamed, infected and possibly need surgical removal.
You should frequently allow your feet time to ventilate to prevent the breeding of bacteria and other microorganisms. Wash your feet daily, keep them dry, wear the correct footwear, and like your hands, keep them moisturized.