What Works for Dry Skin?

i have had dry skin for a while now. Its mostly my legs and my feet. i have tried a few different moisturizers but they don't seem to improve my skin at all. My mom also has very dry skin but hers is worse. Her feet and hands get cracked because they are so dry. I think it is hereditary. So i want to do everything to help prevent it now, before mine gets that bad. Does anyone know anything that actually works and improves the skin? Thanks alot ppl