In the course of scientific experiments it has been proven that any habit can be instilled in 21 days. Of course, you need to understand that 21 days is a conditional figure. Some habits can take up to 60 days to develop. But three weeks is enough for the habit to take hold in the subconscious. And then it will be easier to do or not do a certain action.
Not all at once
You should not take to instill all good habits at once. It won't get you anywhere. It is better to focus on one, especially if it is difficult. For example, changing your diet or exercising regularly. Easier habits (fold the bag in the evening, wash the dishes immediately after eating), you can take two or three, but no more. And it is better to develop them sequentially, not in parallel.
The habit of using a rubber band
There is always a desire to break loose, to start doing as it is convenient for us, as we are used to. Let's say you decided to give up tea with sugar, but at some point you could not resist. In this case, a rubber bracelet on the arm will help. Pulling and letting go, clicking your hand painfully enough for the negative reflex to take hold. Another time, you will already think about whether to drink tea with sugar.
Accounting for days
To form a habit, you should start a habit tracker. Mark the days to make it easier to keep track of how much time is spent on bringing an action to automatism. The missed days will also be clearly visible and how much is still left until the moment when the new habit is finally formed and consolidated.
The fact that the habit has become entrenched and become second nature will be evidenced by the discomfort that arises. You haven't done your exercises, haven't washed your dishes, and all day you feel uncomfortable. Therefore, you have brought your habit to an unconscious state, to automatic actions.