There is a single glass that lives to the left of our kitchen tap. It is not a special glass. It is slightly cloudy from the dishwasher and a little chipped at the rim. But it has a home, and because it has a home, we drink from it more than we ever did when the cupboard held a tidy stack of identical ones.
The idea is almost embarrassingly simple. A glass you have to fetch is a glass you fetch when you remember. A glass that is already there, in the same spot, catches your eye each time you pass. The remembering is done by the place, not by you, which frees you from the small tax of having to think about it.
We refill it through the day without ceremony. Passing to grab a tea towel, we drink. Waiting for the kettle, we drink. None of it feels like a task because none of it has been turned into one. The habit is woven into routes we were already walking through the kitchen anyway.
We are not going to make claims about how much anyone should drink, or what it does for you, because that varies from person to person and is properly a question for a qualified healthcare professional. The habit here is not about a number. It is about reducing the friction so that the easy, ordinary act happens a little more often.
If you try one thing from this, let it be the fixed spot. Choose a glass, give it a home by the tap, and leave it there. The point is to stop relying on willpower and start relying on geography. Geography is patient. It is in the same place every single time you look.