The bedside water I actually drink
On the small glass of water by the bed — and the strange way it has improved my morning skin more than the eight glasses they tell you to drink in the day.
There is a small glass of water on my bedside table every night. The glass is small — maybe two hundred millilitres. The water is filled at the kitchen tap the same time every evening, around ten. The glass sits beside the lamp. In the morning, before I get out of bed, I drink the water, slowly, in two or three swallows.
I have been doing this for about two years. It is the simplest of all the hydration practices I have tried, and it is the only one that has produced a visible difference in my morning skin.

The eight-glasses problem
I had spent years trying to drink the recommended eight glasses of water a day. I had bought the marked bottles. I had set the phone reminders. The reminders were either ignored or, worse, succeeded — I would drink two large glasses in fifteen minutes to meet the morning's goal, then make four trips to the bathroom over the next hour, then dehydrate again.
The eight-glasses approach was treating hydration as a problem of total volume. The body, I have slowly come to understand, treats it as a problem of distribution. A small glass when the body is most dehydrated is more useful than a large glass when the body is already topped up.
When the body is most dehydrated
The morning, after seven or eight hours of sleep with no water intake. The skin at this point is at its driest. The kidneys are at their most concentrated. The blood is, in literal medical terms, slightly thickened. The small glass on waking is the single most well-timed glass of water in the day, and it does, for the skin and the eyes and the head, more than the equivalent volume drunk an hour later.
On the visible result
The morning puffiness around my eyes, which had been a feature of my mornings for years, has been measurably reduced. The skin on my hands is slightly less papery. The small dryness at the corners of my mouth, which used to require a balm in the first hour of the day, has gone.
I am not drinking more water than I used to. I am drinking the same water at a slightly different time. The small redistribution is the entire intervention. It costs nothing. It takes ninety seconds. It is the single most useful change I have made to a hydration routine and it took me years of more complicated approaches to arrive at.