In order to help make sure I get 8 glasses of water a day (because I am horrible at remembering) I have one for every hour I am at work. Not only does this help get me away from my desk and walking around for a couple of minutes, it ensures that I have my 8 cups before I leave for the day!
But don't take any fluctuation, up or down, to heart. Spark is about learning how our bodies work - how they react to the sodium from yesterdays nachos, how they retain water after hard work outs, how fast we can lose water weight.
I find that when writing notes as reminders to do chores, if I address them to myself as if I was my own significant other I'm more likely to do them. "Sweetie, could you take out the trash, please?" is just much more loving and caring than, "Trash."