I've been around the trading block (and back again) and this is where I am at.
The only trading information I will consider looking at nowadays is self improvement.
Particularly self awareness and self discipline. (Retail traders do not have the benefit of a manager to tap on our shoulders and enforce we lighten up our exposure.)
I believe my self improvement efforts have helped me just as much (if not more) in my personal life as in trading.
I have gone down many routes from Daniel Kahneman to the American motivational speakers.
The OP has mentioned self improvement a couple of times and I would love to hear about his self improvement journey his study of topics and his resources used. Books, courses, training whatever has helped him.
So little of the trading world attempts to deal with this information. I used to find it very frustrating looking for the information/books/traders that/who connected the two fields.
In the end, the things I did completely outside of trading helped the most and once the connection was made that:
1. Any improvement to my life in general improved my trading, and
2. Principles learnt outside of trading could be applied to my trading to improve results.
...I stopped looking for answers within the trading world.
Now, I'm trying to merge the 2 worlds, the "gooey" hippy world and the "prickly" trading world. (The words "gooey" and "prickly" are used by Alan Watts btw, his stuff is amazing, try to find recordings without the distracting backing music though...)
Anyway, in answer to your question, here are things that have helped:
Yoga - If I had to choose one thing, it would be this. Teaches me acceptance, calms the mind, keeps me fit physically, the list is endless. Ideally alone and in silence and if I can, outside.
Mindfulness - Being aware of my thoughts (essential in trading) being present and living the moment, whatever that moment may be. I would recommend the 8-week MBSR/MBCT course as a starting point.
Minimalism - Not for everyone, but helps me enormously. It is important for me to keep a clear space as it helps me have a clear mind. It can be hard living with people who like "stuff" but it's worth me persevering because clutter has a negative effect on my trading mindset.
Also, helps re-evaluate financial priorities and think about why I trade in the first place. My trading is also pretty minimalist
Exercise - Especially time in the outdoors, walking in nature alone, essentially another type of meditation, but will all the added physical benefits.
As for books, I found Michael Martin's "The Inner Voice of Trading" helpful when I was trying to link the hippy stuff with trading. It is not very elegantly written but he talks about the link between trading and yoga, so I knew I wasn't completely mad!
You mention alcohol and weight. This is something I am exploring at the moment. The link between mindless eating/drinking and mindless trading is fascinating. In other words the voice that says "go on have another drink" is the exact same voice that says "go on, take the trade, it's not in your plan but have a punt". So, practicing not reacting to that voice outside of trading (e.g. drinking) strengthens the muscle for when it comes up in trading. That's the theory anyway!