I saw an idea recently about putting times onto your water bottles and knew it would work for me. Here's the water bottle I set up last night.

I decided that I'd make it from 7 am - 7pm. I wake up before that and I go to bed after that, but those are generally the hours that I'm drinking water. I'm just not in too much of a mood before that and I have milk usually with my breakfast and of course if I drink much later than 7 pm I end up with extra trips to the restroom during the night.
This is pretty simple, but in case anyone has questions I'll elaborate on how I set it up. This bottle actually holds more than 64 ounces, so I used my scale to determine where 64 ounces was at, that's my 7 am line. I just fill it to there. Then I divided 64 ounces by 12 hours and realized I should be drinking about 5.33 ounces each hour. This is about 21.3 ounces I should have every 4 hours. Again, I used my scale to get the lines in the correct place. At first, I only put lines at 7 am, 11 am, 3 pm and 7 pm, but I decided I didn't like the big gap between 11 am and 3 pm (due to my bottle's size), so I went ahead and added 1 pm too.
The idea on pinterest was on a 32 oz bottle. I think the user had the times on two opposite sides of the bottle, but s/he may have had two different bottles. The picture showed two bottles, but I just couldn't tell if the pic had been edited to show both sides or if indeed it was two bottles.
Hope this helps someone!