Try to maintain your pet's normal routines as much as possible including normal diet, exercise routines and bathroom breaks.
Take your dog for an extra walk or two every day. Plenty of exercise helps dogs (and all of us!) stay on their best behavior. Potty accidents can easily happen when there are so many people at home that everyone assumes someone else has taken your pet out or when your dog is so excited to play with visitors that he forgets to ask to go out.
Add an extra litter box and a feeding station where ever your cat tends to hide if your cat becomes stressed (hides, misbehaves, etc.) with changes in routines such as guests, noise and excitement. The master bedroom is often a sanctuary for a shy cat, so adding a litter box along with an extra food and water dish there can offer your cat a lot of comfort and help prevent any behavior problems.
Don't feed your pet leftovers or pan drippings. Our most common holiday medical emergency is upset stomach due to over-feeding. Gorging on fatty foods can cause severe life-threatening illness.
Don't feed your pet bones. Poultry bones are especially dangerous, but many kinds of bones can cause problems, especially if fed in excess.
Make sure your pet is wearing an ID tag if you travel together. Pets can easily become lost if they become disoriented when away from their home and routines or if their travel accommodations aren't as secure as their home. Attach a temporary tag (a flag of masking tape works well) to the collar with your cell number or a local number if you will be unable to check your messages on your home phone. While microchipping is always recommended, an ID tag is a more immediate way for your pet to likely be returned if missing.
Prevent your pet from eating holiday decorations, tinsel, ornaments, chemically-treated tree water, etc. Ribbons and yarn are especially appealing to cats and are especially dangerous. Delaying treatment of intestinal blockage or injury can be very dangerous, so if your pet has ingested anything unusual and shows any signs of discomfort or stomach upset, contact the veterinarian immediately.
Don't allow your pets to eat chocolate. It is toxic to pets and can be deadly. Keep all chocolate securely away from those naughty dogs who might help them selves to the chocolate box under the tree or get into the cake on the counter! Contact the veterinarian immediately if your pet eats chocolate, especially if it is a large amount, dark chocolate or if your pet shows any signs of illness or stomach upset.
Don't give your dog hard plastic chew toys or bones. Hard chew toys can damage teeth. Rubber chew toys are is a more durable.