Reverse Tunnel Vision
Tunnel vision is defined as "[v]ision in which the visual field is severely constricted, as from within a tunnel looking out". A tip I've often read is that you should give yourself the reverse problem when shooting.
What do I mean by this? Well, many people make the mistake when shooting of always putting the center of interest in the center of the frame. While sometimes this can be attractive, usually it's not. Try sticking a small square from a post-it note in the center of your LCD screen. If you use the camera's viewfinder, you might try putting a small dot of washable marker in the middle of it (you can clean it later). Try to make your compositions interesting regardless of this area, and you'll come back with amazing results.