Prevention... Popper warm up and use of supportive shoes are important. If you are having a specific problem, have the feet evaluated by a professional.
Couple of things. Good stretching, pumice stone to scrape down calluses and a good moisturizing lotion.
Any pain? The truth is you may not have to do anything special for them particularly if you aren't in any pain. However, if this is your job or hobby and you depend on them, it would be wise to "protect them". Wear sensible shoes, try to stay away from flats as they have no support. If they are tired at the end of the day, you can ice them or soak them in warm water and epson salts, or foot massage.
Dancer. As already stated - callous care and sensible shoes , but I would add regular podiatric care for those things you really shouldn't try at home.
Dancing can. really take a toll on your feet. As a previous dancer I understand the injuries that can occur. It's very important to use the correct products on your feet on a daily basis. I recommend many different natural treatments that can help to prevent and or treat common dancer symptoms such as tendonitis, capsulitis, sesamoiditis, skin blistering and callusing. Always stretch & protect! Best wishes!