>>76396230
As long as you're not doing something like dry fasting or fasting for over 3 days it's very hard to actually hurt yourself. Problems show up slowly and fix themselves by eating.
Otherwise most fasts start the day before by eating the bare minimum you can stand and then you start the actual fast when you wake up the next morning. There's something about sleeping without enough food that resets your brain and makes it easy to not eat long term. It's a good idea to stock some sort of sleep aide.
Aside from improving your life to remove stress and to occupy yourself, what you drink during and eat before and after there isn't much else to think about when it comes to fasting. It's really simple to just not do something.