Dogs bark for a variety of reasons.
  Chiefly, barking is for communication purposes.
  Some breeds are more notorious for excessive barking but every dog will bark at times.
  There are times when you want your dog to bark to communicate with you but everyone gets frustrated with a dog that barks excessively.
  There are generally a few reasons why a dog will bark excessively.
  One of the first reasons why a dog barks is because he is bored.
  Dogs are pack animals, they enjoy daily exercise, interacting with others and social stimulation.
  If they are spending most of their time being cooped up in the house or outdoors in the same yard everyday they may need more stimulation.
Try taking your dog for walks around the block or institute some structured playtime every day.
  This may help to keep your dog from excessive barking if he barks because he is bored.
  Dogs will bark when they are nervous or scared.
  Some dogs are never properly socialized and therefore the slightest thing can frighten them.
  While you are training your dog take him to many different places and have him be around a variety of people.
  Reward him when he is quiet and well behaved.
  A food treat will do wonders to keep him calm in different places and different situations.
  Soon he will start associating being quiet and well behaved with the treat and this will work wonders towards his excessive barking under these conditions.
  Dogs will bark when they are asking you for something.
  However, while you want your dog to communicate with you, you also do not want this type of barking to become a habit.
  If you always respond to his barking he will always continue to bark.
  Try to get him to communicate with you in other ways by praising him and rewarding him for other behaviors.
Otherwise you are just training him to bark.
  Sometimes dogs bark from separation anxiety.
  They just don't want you to leave them and they bark until you come back.
This is disruptive to the neighbors and others so it is definitely something you need to avoid.
  It may be easier to do this if you start when your dog is still a pup and put him in the crate before you leave.
  That way he is safely in his own space and he will not miss you nearly as much.
  Also never make a big deal out of leaving but just quietly slip away.
  He will probably notice that you are gone but he won't be so vocal about it.
  Dogs bark to protect you and there are situations that we all would appreciate that.
  However, every single day when the mailman comes to deliver the mail is not one of those times!  This is a time when socialization and training can really pay off.
  Go with your dog to meet the mailman, let them become acquainted and hopefully your dog will not bark at him everyday anymore.
  Another way to get him to stop barking at inappropriate times is to distract him with a toy or a treat.
  But in the case of your dog barking to protect you remember that there may come a time when you will appreciate that so limit your training to people you know.
  There are many ways to help curb excessive barking.
You can hire a professional dog trainer that can offer you some tips.
  Oftentimes more socialization and more playtimes will help him to bark less.
  One thing to keep in mind though is that usually your dog is barking for a reason.
  Find out what that reason is and then deal with it.
  You will enjoy your dog more and other will also enjoy your dog more if he doesn't bark excessively.
  Try to stop the negative behavior of excessive barking while your dog is a young puppy and when he is older you will know that if he is barking he has a good reason.