Lord knows that water is probably the most boring drink on the planet. But it’s also the most essential. Spend a day fully hydrated and you’ll notice that a) you need the bathroom a lot more and b) you function about ten times better than usual.
It starts by just paying attention. Are your lips dry? Sip water. Headache? Sip water. The more you do it, the easier it gets. It takes time to form a habit, so don’t beat yourself up if you don’t go from one glass a day to eight overnight.