While not every method works for every pet here are some things that may be very helpful for your pet.
Most IMPORTANT...for dogs. Get their business done early, and stay with them if in your yard; have a firm grip on their leash when you walk them, then keep them in the house! Only last week, a dog was peeing in the yard when a loud firework went off, and he jumped the fence. I don't know if he's been found yet.
Make sure their ID tags are up to date in case they get out. Even if they're chipped, they may not be found.
A "Thunder Shirt" can be helpful for anxious dogs. Even a thick T-shirt can be comforting.
Some calming meds from the Vet can help. Don't give human tranquilizers or any pills!!!
Rescue Remedy can also help with anxiety. Oliver's has it. They may run out at this time. Or give them a calming remedy like Cat Nap (for cats only) or Chill Out, Canine Calm (for dogs only)
Put your pet in a crate or a room away from the noise Leave the TV or radio on to mask the noise. Close the drapes
Play and run them in the few hours before the festivities begin. A tired pet is more apt to sleep or veg out during those hectic hours.
Do everything you can to provide safety for your pet. Losing a pet doesn't have to happen if you plan ahead for this terrifying experience.