I use baby oil (good old Johnson & Johnson) on my hand every night....And I believe it really helps.
When I shower, I use Skin-So-Soft oil (Avon) directly on my wet hands....seems to help retain moisture a great deal.
I think I remember reading somewhere where Doris Day used petroleum jelly thickly on her hands and then put those old white cotton gloves on...to sleep in every night...She did not want her hands to "look old."