The first thing a dog owner needs to buy

Buying a collar and lead is probably one of the first things a new dog owner does as they are a necessity for proper control of your dog and an essential piece of equipment when training a new dog or puppy.
If you have a puppy then it's likely they will quickly outgrow a collar or lead, so it is perfectly acceptable to buy non-expensive and lightweight equipment during this early stage of their life.
Many people like their dogs to wear a collar all of the time, but some ornamental collars will not stand up to a sudden movement or constant straining. You should therefore consider having 2 collars; one for ornamental purposes and another one for training your dog or puppy.
Even though puppies get plenty of exercise through play you should try and get your puppy accustomed to wearing their collar and lead at the earliest age possible.
Even if you do not intend your dog or puppy to wear a collar all the time you can buckle a light collar around their neck and leave it there for a number of days until your dog or puppy ignores its presence.
Do be aware that the neck hair of a long haired dog will be permanently marked if it wears a collar at all times so use common sense depending on your breed of dog or puppy.
A bolt and spring clip is best on the end of a lead and you should buy clips where the opening does not come at the point of most strain as they are liable to come apart.
Leather and nylon leads are a good choice and although many owners think chains would be stronger they can be very uncomfortable from the owner's point of view.
If you are serious about training then you will be using a slip collar as this will provide you with much more control. A slip collar consists of a chain with a ring at either end, the chain is dropped through one of the rings to form a loop, which is then put over the dog's head.
A pull on a slip collar is slightly uncomfortable for the dog providing focus for training, but when the lead is slack the collar is loose. The slip collar will only work well if the collar is put on correctly so you should practice to ensure the fit is best for you and your dog.
When using a lead take it in your right hand and ensure your dog walks on your left hand side. If using a slip collar the ring through which the chain is slipping should be underneath. Practice as much as possible with your collars and leads so that both you and your dog or puppy become familiar with them and you can both use them in the best possible way.
Once you have the right equipment you can begin basic exercises and lessons to train your dog for obedience, competitions or shows, providing pleasure and companionship for you and your dog or puppy.