For starters you should definitely bring along your best or favorite driver with you to the driving range. This should be the driver that you are most familiar and comfortable with so you have the ability to continue the special owner/club bond. The more you swing a certain driver (or any club), the easier it is to consistently use it over and over again effortlessly. Having your own personal driver on the range allows you to test the limits of yourself and that driver--you'll be able to see exactly how hard, fast and far you stroke the ball without the repercussions of hurting your score. Knowing your driver's capabilities is essential to becoming the best possible golfer that you can be.
You should also bring to the driving range items that can assist you in correctly executing drills and practices. Items such as a quarter and/or a stop watch can go very far in helping you achieve what you need to at the driving range. For instance, using the stop watch can help time your drives to see exactly how long it takes you to back swing, down swing and follow through, as well as how long your ball is in the air after a drive. The quarter can be used for a specific drill called the "give no quarter drill," which is a very effective drill in terms of teaching a golfer how to properly turn her body and drive the ball successfully. To learn how to execute this drill, see the article "Drills to Help You Drive Better" at golflink.com.
Water or Beverage With Electrolytes
The final thing you need at the driving range is water or a beverage with electrolytes (Gatorade, Vitamin Water, Powerade etc.) in it for hydration purposes. Some days at the driving range can be very hot due to the lack of shade and trees. Even on days when it isn't so hot, heat exhaustion can still be an issue due to the energy you are expending on every swing.