heres what i do to help me keep track of how much water i am drinking. my water bottle holds 3/4 of a liter (approximately 3-8oz glasses of water..but thats neither here nor there, sorry )
i know i need to drink 3 of them a day, 4 on days i hit the gym. i was constantly losing track of how much water i had drank.
so what i did was put 3 red rubber bands and 1 green one around my water bottle. the red ones are for my daily requirements. and the green one for when i work out or as a bonus water on days i dont. everytime i refill my bottle i move a rubber up.
hope someone else finds this as helpful as i have!