I am one of those people that is glued to my smartphone. I know a lot of my friends are, so maybe a bunch of you gals also are. If so, the most awesome application I found was the "drinking water" app.
I put in how much water I want to drink each day, and between which hours my day runs. Everytime I've not tapped the icon that represents one cup of water for a few hours it buzzes and notifies me to drink water. It's super simple but SO effective.

