Mirror the profile of actually happy, older people who have lives you would like to have.
Take care of your health, eat well and exercise.
Be successful: you don’t have to be rapacious, but there is a level of financial success and stability that definitely decreases stress and affords more opportunities, like travel and hobbies.
Be social: the happiest people have strong social networks.
Be wise: don’t worry about what you can’t change, but be engaged and try to make the world a better place.
I sea what you did there!