Moisturise, Moisturise, Moisturise.
Moisturizing is must whether you are 20 years old or over the 40s, But the difference is women with mature skin have to Take care of Their skin more often and moisturize as many time as they can. Hydrating skin and body is the very first step to look good even after the 40s.
Use Good Quality Moisturizer and Keep Applying it after every few hours. Hydrate your body internally as well, Drink Fluids more often.