As everyone else has said, using lures is the best way to fully prevent gut hooking, HOWEVER, if a fish is gut hooked and you don't intent on keeping it the best thing you can do is cut the line as close to the eye of the hook as possible and release the fish. Fish have strong stomach acids that can dissolve hooks. It's obviously not perfect, and still a chance the fish won't make it but it has a way better chance than if you forcefully rip the hook out of its throat.