You can buy vinyl background "clings" at the pet stores that you can cut to size and apply to the outside of your tank; those give more visual appeal. You can also look in aquarium sections of stores for smooth rock-type decor that would work for additions to your tank. If you decide to switch from paper towel, you can use tile from Home Depot-type stores. It's easy to clean, and their colors look a little more natural. Craft and thrift stores have inexpensive fake plants of different types that would give you a little variety.