Our feet sweat more than the rest of our body and spend most of the day cooped up inside socks and shoes, so they don't get much room to breathe. Because of this, you should focus on including a daily foot washing routine to prevent bacteria growth, fungal infections, and foot odor.
You only have to wash your feet with soap and warm water, when you're in the shower or you can wash them under a faucet. Pay special attention to the areas between your toes, as this is especially suited for the growth of bacteria and fungi. Don't soak your feet in warm water for extended periods of time; this can dry out your skin and destroy its natural oils, increasing your odds of cracked heels.