Call your local city/county government’s Animal Control. They might have some good ideas, like trapping and relocating the fox, or sprays or other repellents to keep it away. Shooting stuff at it won’t help. Foxes are smart – it’ll just come around when you’re not there. Unless you want to get a dog and keep it out in the yard most of the time.
Why is it worrying you? Do you keep chickens or something that you’re afraid it will eat? Then it would be a good idea to critter-proof their pen. And if you’re keeping chickens, check with your local zoning people. In some places it’s against the law and you could get hit with an expensive fine. If you’re afraid it will eat your cat, just keep your cat inside. For a small dog, just never let it out without you. Foxes have a reputation for being smart, and they deserve it.