Dogs are one of the most popular pets in the world, and one of the first animals known to be domesticated.
They are often loyal, protective, and helpful, and tend to make wonderful companions for years as long as they are taken care of properly. Obviously, the first step comes in choosing a new dog. Young puppies are often best, especially when there will be children around, as they will get a chance to grow up learning how to act around you. Puppies are also much easier to train, since they haven't become set in their ways yet.
There are a multitude of breeds, cross-breeds, and half-breed dogs out there, and you need to decide if you're looking for a pedigree or specific traits. If you want to be able to prove that your dog is purebred or that it comes from a specific line, select a kennel that sells pedigreed dogs and be sure to get all of the information about the parents and an application to register your dog with a kennel club. If you're looking for specific traits, check in on the traits of various breeds (such as Labradors, beagles, etc.) until you find a breed that tends to carry the traits that you seek (such as good hunting dogs, water dogs, etc.) However, if you're just looking for a dog (as opposed to a specific dog), you might be better off to stay away from the kennels and go to either a local pet store or to the pound.
Pet stores will cost a little more (but still less than a breeding kennel), but the conditions that the dogs are raised in will be more or less consistent. A pound or animal shelter will cost much less (often $25 or less), but the dogs there come from a variety of backgrounds. Some may be mistreated, or strays, or might have just not been able to find a loving owner. Many animal lovers will encourage you to check out the pound first, since animals at most shelters (other than "no kill" shelters) are only kept there for a few weeks before being put to sleep. Once you've found the perfect dog, it's time to bring it home. It's usually best to try to bring puppies home in the morning, to allow it time to get used to its new surroundings before bedtime. You should also try to get the puppy at a time when you or someone else will be around a lot, since most young puppies will get quite sad after being separated from the rest of their litter or other dogs.
Young dogs, especially those just weaned, have very simple lives. They eat, they sleep, they go to the bathroom, and they play. You should have sleeping quarters for the puppy ready before you bring it home, and put it in its bed whenever it starts to get tired. Eventually, it will get used to sleeping in that area, and will return to that same spot whenever it feels like taking a nap. You should also make sure that you have a few toys for the puppy to play with, and encourage it to play only with those toys. After all, puppies are going to chew on something... if there isn't anything that you approve, then it will likely find a shoe or other object and think that it's fair game.
Feeding schedules are very important for new puppies. If your pup is under 12 weeks old, you should try to feed it 4 times a day (making sure to use soft foods), gradually shifting it over from whatever brand it was used to eating before. From 12 weeks to 6 months, you should reduce feeding to 3 times a day (again, staying with soft foods.) Feed 2 meals per day for dogs aged 6 months to 1 year, reducing to 1 meal per day (depending on size and weight) after 1 year.
Once your dog has been fed, it's going to have to go to the bathroom. Take young pups outside about 10 minutes after they stop eating, and stay out until they've done what you're there to do. Praise them, and take them immediately inside; they'll start to get the picture that they're out there to go to the bathroom. Housebreaking pads and other training aids can also be used to help get the dog used to the idea that the outdoors is the proper place to use the bathroom. Best of luck with your new dog. Hopefully, you'll have a friend and companion to share your life for years to come.