How To Change Someones Behaviour For Real

If you want someone to perform an action you first need to make it visible to him/her. Let’s say you want your husband to make exercise on a treadmill.
All you need to do first is that he recognized the treadmill as present in a room he would regularly visit.

Putting the treadmill in a distant place makes it more unlikely that he will start doing it. Then you need to make it rewarding for him to start exercising.
For instance the only way he can surf the internet on his phone is when he is doing exercise. That is because the
treadmill produces electricity for the router. The surfing experience connects the exercise with a good experience. So whenever in the future he thinks about exercising he has a good feeling towards it.
So whatever you want someone to do the task or action needs to be easily available and connected with a nice experience that he can only have if he performs the action so that he remembers it as something nice. And there are absolutely no workarounds to cheat on it.

On the other side, let’s talk about changing bad behavior.
Whatever might be the bad behavior it needs to be hidden as well as possible. Make it very hard to get. Then there needs to be a punishment for doing the bad task that is more punishing than the habit gives reward. Also, make the task as complicated to fulfill as possible. For instance, put a lock in front of the fridge that has an incredible long code to unlock it. Last when performing a bad habit give all the personally relevant good things that come
with avoiding the habit.
If you want to do this to yourself start with a list of all the bad and good things you do to get first aware of them.

Source Atomic Habits James Clear