Crisco. Seriously. Think of it as soy butter. I even mix in a bit of EO (usually lavender) sometimes.
I put it on after a bath or shower, while my skin is still moist. Rub it between your palms first, to liquify it, and then apply. For feet, I rub it in, put on socks and go to bed. I wake up with very soft feet.
I once worked with a man whose hands were so dry they were cracking. I told him about Crisco. He got a pair of cotton gloves. He washed his hands well, rubbed the Crisco in, and put the gloves on over night. This was over a weekend. The next Monday morning at work, he came to my office to tell me what a difference it had made!