Excellent question with not one answer unfortunately.
For the young, the key is to prevent aging, for the old, the key is to reverse aging. For young people, the key to maintaining youth is to do things that prevent aging:
- avoid smoking
- avoid UV radiation exposure - including sun and tanning beds
- avoid stress
- moisturize your skin
Avoiding UV exposure is problem the biggest thing that can be done to prevent the signs of aging. UV exposure not only increases the risk of skin cancer but it also causes cellular changes which cause wrinkling of the skin and loss of skin elasticity.
For older people, the key is to reverse the signs of aging:
- Lift the brows into a more natural position
- moisturize the skin
- remove excess upper and lower eyelid skin
- remove wrinkles from around the eyes (this can be done with several treatments both surgical and non-surgical)
- remove bags from under the eyes
- replenish cheek fat
Some of the procedures you can research include Botox, facial fillers such as Juvederm and Restylane, fat augmentation, skin resurfacing with deep chemical peels or laser, IPL/photofacial treatments. All of these will help to reverse the signs of aging.