I've never given it much thought, but i suppose soaking your fingertips in warm water and then applying moisturizing lotion or something afterwards? Ohhhh, if you dont mind spending money, buy Mary Kay Peach Satin Hands set; it works a charm on my sister!
For any dry or cracked skin, which I often have, I use the dermatologic product "eucerin". Don't know if this brand would be available in Germany. But it works. When the problem is not severe, using 1 time solves it. When any skin is really dry dry, 2 to 3 times will generally make it (stay) elastic. Hope this can help you :-)