Sticky Notes! I use these things all of the time as reminders. I stick them to my computer monitor to help remember tasks that I need to get done throughout the day, but they also work wonders in helping you stay motivated! Write inspirational quotes on them and place them in places that you visit often during the day such as your bathroom mirror, refrigerator, the snack cabinet, your desk, and so on.
If you sit at a desk most of the day, purchase a small chalk board and write something on it that is inspiring to you. You can change it daily depending on what your motivational needs are.