Fill your water bottle right now and put it on your desk where you can see it.
Not in your bag. Not in the kitchen. Right in front of you.
Visibility is the single most effective behavior change tool for hydration.
If the water is in front of you, you drink it.
If it is out of sight, you forget it exists until the afternoon slump hits and you wonder why your energy dropped.
Water. On your desk. Right now.