Work out ( but not too much especially not cardio) , i can't find the study about it at the moment but i remember one where it said that even healthy people that do too much cardio are at a risk for heart attacks.
https://fitness.mercola.com/sites/fitness/archive/2012/06/01/long-cardio-workout-dangers.aspx Eat well , not too much red meat , a balanced diet is the best try to avoid too much alcohol and cigarettes are a huge nogo
also don't take too many recreational drugs. Antioxidant foods like wild blueberries should in theory slow down cell death and your bodies' "decay"
And i've read mixed things about a ketogenic diet where you basically don't eat any carbohydrates and your body runs on fat , but do your own research on that topic
i haven't tried it myself yet but i'm planning on trying it in the near future because of the apparently heightened mental capacaties that people report while their body is in the state of ketosis
Do things for mental health , transcendental meditation for example seems to reduce the risk of cardiovascular diseases because of lower cortisol
there are other things like Qigong and even yoga that seem to reduce stress.
Et Cetera
Also you should know that just living long isn't really great when your body get's worse by the year being 90 years old doesn't really sound appealing to me when you're in constant pain
or get alzheimers or other illnesses. Maybe science will have a fix for this when we're that old, let's hope !