The first is to accept that aging is inevitable. If we can believe some of the marketing people, our ages can be held back by their products - or almost: we will look younger. We might, until the
Botox needs replacing, or the anti-aging skin cream turns out to the farce it always was.
So after acceptance that our bodies will keep replacing our molecules in an 'almost the same' pattern over and over (it's never quite the same, that's why we age) the second is to keep ourselves healthy in body, mind and spirit. Yes, all three come into it. The body needs good, wholesome food (and not too much of it) exercise, adequate rest - you should know all this stuff
The mind needs to be kept exercised, too. Keep learning, keep exercising it by using it - rather than it using you (you HAVE a mind, but you are NOT a mind)
Thirdly, you highest values, goals, and priorities need keep you from compromising your happiness on lesser things. Happiness, helps health in both mind and body. The spiritual side of you is every bit as real - and is probably the most important - part of you, so allow it to keep you motivated towards the reasons you want to ...age well.