Cracked heels which are medically called heel fissures never look good, can be a real nuisance but as they can occasionally lead to more serious problems if they are not treated you need to take them seriously. They are more common in those who have dry skin, are overweight and wear shoes that have an open heel. The best way to treat them is just giving your feet a little more attention by beginning with applying a moisturizing cream them at least twice a day to start with for the dry skin. Once a day after it has improved will probably be enough. Look for moisturizers or creams that have a thicker consistency. Some of them contain skin-softening agents, such as urea and salicylic acid which may help remove dead skin.
If the cracked heels are not helped by that regular use of cream, then see a podiatrist. They will remove the thicker dead skin and then if you apply the cream regularly after that, then that should help keep it under control. You could also give your feet some extra attention before going to bed by soaking your feet for about 10 minutes in plain or soapy water. After drying the feet then gently rub your heels with a foot file or something similar to help remove dead skin. Apply a heavier, oil-based cream and then cover with a pair of thin cotton socks or silicone gel heel cup at bedtime to help the moisturizer work. Also try and address the risk factors for the cracked heels. Losing weight over the long term will help and try and avoid wearing shoes that are open in the heel area,
Above all, don't ignore the dry cracked heels as you may develop deeper fissures in the skin which increase your risk of infection. If the above self care measures don't help, talk with your podiatrist about other treatment options that you could have.