Let's start with Christmas table.Let your guests know that they shouldn't give anything to your pets.Turkey,chicken and lamp skin may cause severe gastrenteritis.
Sauce and oil from cooked food should be kept away.Bones could cause obstruction or injury of digestive tract.
Chocolate especially dark may cause toxicosis ,raisins and nuts as well.
If you have a puppy take into consideration to put the Christmas tree higher to protect from cords and decorative elements.
If your kitty is naughty be careful with Christmas ribbons.
Also poinsettia plant,very common Christmas gift, is toxic for cats in case of eating.
Finally consider to use pheromones (adaptil,@feliway_greece ) and cbd oil from @earthgoodies in order to reduce stress.