Have fun, be active. Ride a bike instead of driving, for example.
The brutal reality about aging is that it has only an accelerator pedal. We have yet to discover whether a brake exists for people.
Deepen your existing spiritual commitment.
The more things for which you develop a fondness the richer the life you live.
Inconvenience yourself: ditch the remote, the garage door opener, the leaf-blower; buy a bike, broom, rake, and snow shovel.
You rarely get satisfaction sitting in an easy chair. If you work in a garden on the other hand, and it yields beautiful tomatoes, that's a good feeling.