1) Talk to G-d every day
The single best way to keep you soul in tip-top condition is to talk to G-d every single day.
If you want some help or encouragement to start doing this, you can download 'The How, What and Why of Talking to God' for free until Sept 1, by clicking HERE.
2) Work on your negative emotions
Don't just tell yourself that you got 'stuck' with a bad temper, and there's nothing you can do about it. For example, our sages teach us that angry people die young - and there's broad agreement in the medical world that fear and anger are a couple of the most damaging, unhealthy emotions there are.
Fear and anger don't just disappear by themselves the older you get; in fact, the opposite is usually true. The more people leave their negative emotions, and try to deny them or ignore them, the worse they get, and the more damage they do.
Any spiritual effort we make to work on our negative emotions, and clean them out of systems, will pay massive dividends for our spiritual and physical health.
3) Keep as many commandments as you can
Jews have 613 laws to keep, governing pretty much every area of our lives. G-d doesn't want us to only eat kosher food, or keep Shabbat, because we're doing it for Him. Part of the reason He gave us all these commandments is so that we'd keep a strong connection with Him, which in turn would maximise the Divine energy and light flowing down into our souls, and subsequently, all around our bodies.
Every time a Jew eats something kosher, they are connecting their soul back to G-d, and getting a strong blast of holy, healthy spiritual energy flowing through their body. Every time a Jew eats something traif (unkosher), it disconnects them from G-d, blocks the Divine light flowing through their soul, and severely compromises the Divine energy flowing through their bodies, leading to emotional and physical issues.
(If you've ever wondered why 'healthy eaters' can often appear to be more spiritually-orientated, the same idea is at play.)
Every time we avoid gossip, we're cleaning out our internal environment, and enabling our positive emotions and characteristics to shine out of us. Again, happy, generous, kind, thoughtful people have much more Divine energy coursing around their body, and tend to be much healthier in all senses than people who are full of gossip and negative emotions.
We're not going to go through all 613 laws here, but you get the basic idea: more commandments = more connection to G-d = more Divine light in the soul = more Divine energy in the body = happy, healthier people.
Take a look at the free Talk to God and Fix Your Health Course over on the jemi website, if you want some help to start dealing with your negative emotions in a spiritually healthy way.