A dog needs to be socialized as earlier as possible - their critical period is 4 to 14 WEEKS. When you choose a puppy from a breeder, be very aware of the situation it has come from - was the pup born in somebody's home, have the puppies been left in an area where only the breeder has had any contact with them, does the breeder play with them, has the pup been with people, children, other animals (cats, for example), how old are the pups (ideal age, in my opinion, to get a puppy is around 8 weeks - if they are any younger, they still need their Mum!)? A mother will start the training (manners!) for you when the pup is born but you must learn a little about your pup to continue her training.
Understanding and respect are the two key elements to training your dog. If a dog works out of love for you, it will follow you to the end of the world ... and back! You cannot trust a dog that works out of fear, so be kind to your puppy and take the time to learn a little about how dog's think before you start your training. What a puppy learns in it's first twelve months of life is primarily it's imprint for life! This doesn't mean you can't teach an old dog new tricks but it might take a little longer to break old habits!
Try not to have conversations with your dog when you are training, you will only confuse your pup ... keep it simple, keep it consistent. Use simple words like, Sit; Stay; Heel. Reward your puppy with a gentle, happy tone and a cuddle or a food treat. (Please don't give your dog chocolate - it is poisonous to them - as are onions - and dogs have died from chocolate toxicity.)
Taking your puppy/dog to a Dog Club is very important - even if you only go for a few months. Don't be put off by the words "Obedience Training" - not everyone who goes wants to take their dogs to the lofty heights of Obedience Trials and/or Showing! It is important, however, that your dog gets as much socialization as possible with other dogs - and people, young and old. Dogs don't recognize babies/toddlers/young children as the same as you and I - for a start, they are much smaller and smell different! The training will help to teach your dog some manners and to pay attention to you. You can teach your dog training skills out of a book or from a video but you can't teach them social skills from your lounge room! I have lost count of how many people have said to me that their dog will do the skill at home but when they first come to Dog Club it just won't do it! The dog needs to learn to listen to you and to be so at ease with the other dogs and people so that seeing another dog when they are out with you isn't something out of the ordinary. It can also be a lot of fun and you meet some interesting people with whom you share a common interest and goal.