First ingredient and most important is also the simplest. No alcohol. None. Nada. Zip. SFA. If you intend on seeing permanent recovery to your cognitive ability, that means for good, too.
In my opinion, sleep is the next most important thing. That needs to be solid. I have OSA, so I was fighting a loosing battle until I got the CPAP happening.
Next, I think that regular moderate exercise follows. This gets the blood and oxygen moving around. Finally, I recommend a simple and varied diet with a minimum of processed foods, stressing fresh ingredients, and protein, fats and fiber with complex carbs as you require.
This has what has worked for me. And add patience, grasshopper. We are in this for the long haul.