Part 1 of our "Puppy for Christmas" checklist covered preparation (occurring roughly Dec. 1 through Dec. 24). Now let's focus on the Big Day!
1) Be prepared for everyone in the house, including the puppy, to go crazy! Everyone is going to want to hold the puppy. Everyone is going to want to play with the puppy. Even if your new puppy is already house-trained (doubtful, by the way) all that excitement could lead to a surprise that you *don't* want (i.e. a piddle party). Have the primary caregiver (be it child or adult) take the puppy outside for a break every 10 to 15 minutes. After all that excitement dies down, the puppy will probably fall asleep (as will the kids and adults no doubt! :^) Remember, ALL the people and ALL the rooms of the house are new to this little one. Showing him/her where *everything* is (especially the "bathroom") will be a huge help!
2) Socialize, socialize, socialize! I'm going to quote a professional dog trainer here (Barbara Long of "Paw In Hand Dog Training") because she took the words right out of my mouth:
The most important skill for a dog to have is to be good around people. Ian Dunbar MRCVS, believes that a puppy should meet 100 people, at least 20 of them children, before the pup is 12 weeks of age. She should meet both men and women, all races, ages, wearing hats, glasses, carrying bags, backpacks, walking with crutches etc. You want your puppy to think that she would rather meet new people than do almost anything else. Teach your pup "sit" for an extra special treat and then have her sit for every new person she sees. Keep giving her treats, verbal praise and petting. The person can also offer her goodies. The presence of the person becomes a predictor that good things are about to happen. Most pups enjoy all the attention. Soon your puppy will seek out new people.
Socialization also includes getting your puppy used to other puppies and other adult dogs. So the value of that puppy class offered by your local humane society doubles in this regard. You learn how to work with your puppy and your puppy learns how to work with you AND how to behave around other puppies/dogs. Having your puppy meet adult dogs is a little bit different, so ask your puppy class instructor for tips on that especially.
If you have any questions for me, please put them in the comment section. If there is demand, the "Puppy for Christmas" checklist may have a Part 3.