K.A.
Smile a lot? Smiling is supposed to use more muscles in your face than not smiling. Other than that, plastic surgery? Don't age?
There is absolutely nothing you can do. It's going to naturally happen as you age, as your skin naturally looses it's elasticity. Best you can do is take care of your skin by staying hydrated, not smoking, eat healthy etc.
There is nothing wrong with getting old. It means you've lived life. Wrinkles and all.