It depends on the person and their genetics. The further you get from the ERa the more complicated this gets and simply stating "Do X" wouldn't apply to everyone even if there are some incredibly common things to do. I might know all the upstream genes, their interactions, and symptoms by heart so it is pretty easy to identify, but general advice would go something like: eat well, get sleep and exercise.
I've read that specific type of exercise (repeating cycles of low impact move, cycling, rowing, elliptical machine) are the most effective at triggering cartilage growth. Is that accurate?