I use a 16 oz glass with a lid and straw and fill it with water with lemon slices from the fridge. I try to drink one glass every two hours starting at 8. So I refill at 10, noon, 2 and 4. This gets my 8 glasses of water in and room for a little extra. I don't fuss if I fall behind the schedule, just try to stay within an hour on either side.