There is nothing worse as a dog owner then a dog who continually behaves badly. From barking all day and night, chewing up everything in sight, to biting nothing can strain the owner/dog relationship more than bad behavior. If this is your dog then some form a obedience or behavior training is in order. It will more then pay for itself when you consider the cost of the damage he may have done in the past and the future.
Probably one of the most annoying dog behaviors is continuous barking. The thing to remember is yelling at your dog is not the answer to barking problems. Many dogs will just bark louder because they think you are having a shouting match. The first thing you need to do is figure out why he is barking. Is something scaring him or is there someone or another dog prowling around your yard?
A dog barking because of these types of things isn't necessarily a problem if he doesn't bark very often. It's when it becomes constant and for no reason that some sort of intervention is needed. Dog behavior training can help with this type of situation. There are a variety of products on the market that are designed specifically to help control dogs who bark to much. There are specialized collars that are triggered when a dog starts barking and either emits a small electric shock or sprays citronella around the dogs face and muzzle. The citronella collars are harmless and work amazingly well if you like the smell.
The most serious behavior problem for any dog is biting. Most communities have enacted new laws that deal with biting dogs much more aggressively. In some cases any dog that bites will be euthanized after the first offense, even if the bite was accidental. This is why teaching your dog not to bite is so important because most dogs use their mouth and teeth even when playing.
If you start stressing the importance of not biting when your dog is still a puppy you will nip any future biting problems in the bud. When puppies play they will use their mouth to nip and gnaw on whatever they are playing with, including peoples hands. This is the time to teach them that they are not to behave in this fashion and biting and chewing on your body parts is not allowed, no matter how cute or fun it may be.
One of the best ways to change the behavior of a misbehaving dog is going to a dog obedience class. This can be especially helpful to the first time dog owner who may be at a loss as to how to fix a behavior problem. Every dog is going to have certain behavioral issue, that's just the nature of being a dog. That doesn't mean whatever your dog is doing can't be fixed either. Someone somewhere has dealt with the same issues and found a way to resolve them.