Get a water container (tumbler, gallon jug, water bottle, whatever is your jam) and make it your goal to finish however many of the containers your goal is for the day. Say to yourself in the morning. “I’m going to drink x amount of these today”
If you are shooting for the stars for a gallon- get a gallon jug.
If you have a 32oz bottle maybe tell yourself “I’ll drink between 2-3 of these today”
Have a 64oz container?- maybe make your goal to finish one of those or one and a half for the day.
Consciously thinking about your daily goal will make you more aware of how much you are or aren’t drinking