A great rule is “reward when four are on the floor.” If all four paws are on the floor, your dog gets a treat or attention. If your dog only gets attention when they jump then it’s a double win – mom’s attention and whatever was on the table.
When possible, remove access to whatever is on the table – push decorations to the center, push in chairs, etc. Sometimes it is easier to control the environment than the dog.
Likewise, be sure your pup has enough interactive toys to keep them busy. More toy attention means less jumping! Be sure to rotate the toys they have so as to keep them entertained and interested.
You can also teach him a “leave it” command: Have your dog on a leash, then show them the decoration. Say “leave it” in a firm, but happy voice and as you say “leave it,” show them a yummy treat and use it to guide them away from the decoration. When they listen, give tons of praise. If they don’t then a gentle “nope,” and say “leave it” again. As your dog gets better, put the decoration back on the table and then walk him up to the table, say “leave it,” and if they hesitate, then drop the treat on the floor. If they jump, say “nope” and use your body to push them away.
Lastly, be sure your dog is getting plenty of exercise. A tired dog is a good and healthy dog.