My preference is to fill a 32 oz cup with water at my desk and then refill it partway through the day. This works for me.
However, a friend had another suggestion. She fills a glass with 8 oz of water when she first arrives at her office. Every hour, she makes sure she has finished that glass, gets up and refills the glass. This gets her moving (even if it's only for 30 seconds and a few steps), and ensures that she has had her full 8 glasses by the end of her work day.