Some medical suggestions from a physician:
1) drink more water and stay hydrated. Dry hands are a sign of dehydration and dry skin. You might be outdoors, sweating a lot, or performing hard, manual labour. No matter what, drink plenty of water (not soda, milk, or fruit juice).
2) use a good hydrating moisturizing lotion on your hands and face every day; avoid oil-based ones for they tend to clog pores.
3) don't overwash your hands; wash them when necessary and avoid using extremely hot water. Luke warm water is sufficient.
4) wear gloves if you work with your hands a lot.
5) if you smoke, stop smoking. Smoking also dehydrates your body and dessicates your skin cells.