1. Avoid excessive alcohol consumption. Your brain is shrinking and cannot manage the usual amount. Also, reflexes are aging, too, and you are less able to protect yourself from a fall. If you do hit your head, your brain, smaller now, is more prone to injury bouncing around inside your skull.
2. Avoid eating too much. You do not need the extra calories. Usually you are metabolizing less energy due to less muscle and less movement. The excess calories will turn to fat with a generalized cellular inflammatory effect that is unhealthy. Think diabetes, heart disease, stroke
3. Avoid a sedentary lifestyle. Use it or lose it! Disuse atrophy leads to frailty, falls, increased risk of dementia.
4. Avoid a solitary life style. You are a social creature and too much time alone increases the risk of depression and suicide. Get out there and have some meaningful if possible social interactions. At least get out of your home.
5. Avoid smoking. If you have been smoking for years, stopping will prevent further loss of lung function and will reduce risk of heart disease and save money in this time of inflation. No, you are not too old to quit.
Bonus
6. Avoid an unbalanced diet. Briefly, eat what your grandparents used to eat. Avoid food faddism, red meat, added sugar.