Barking at night
The simple answer is to ignore the dog. By barking, it is training you to respond. You might have a few noisy nights but you will be showing it that barking is not productive. Certainly do not respond by shouting or scolding. If you do so the dog will only know that its barking has been productive by making you bark as well.

Barking, excessive
The reason for excessive barking in one word is FEAR, and it is frightened because it has not been socialized. It is nervous of every sound it hears and barks in a futile attempt to send the perceived threat away. Sometimes a dog which constantly whines, cries, barks, or is destructive, suffers from skin problems brought about by scratching and licking themselves because of the stress of being left. Generally this is not a problem with dogs which have been socialized through training classes at an early age. The solution is socialization through obedience classes and home management.

Barking when the owner is out
This is a big problem caused by bad owners. The dog is a pack animal and if, as a member of the family pack, it is given the freedom of the home by being allowed to rest on the furniture and sleep in bedrooms, then it will suffer a form of stress when the pack goes off to work because it expects to go with the pack. When people leave home they should not look, touch or talk to the dog for about 10 minutes beforehand. The same applies when coming home: ignore, no talking, no patting, no looking, nothing. This way, the dog understands that its barking has not brought the owner back. If it has been barking while you were away and is rewarded by your attention when you come back, it then thinks it was its barking that brought you back to the house. A dog's bark is said to be worse than its bite. It certainly is for the neighbors of a constantly barking dog left alone for too long, unsocialized and with uncaring owners. Hopefully no readers would permit their dogs to be such a community nuisance.

Barking at the postman
The postman or any kind of regular deliveryman is regarded by your dog as an intruder and so it barks and is immediately rewarded by the postman going away. It thinks it has frightened off the intruder and done its duty. Talk to your postman and try to get him to cooperate. Tell him you will leave a tit-bit outside the door and ask him to push it through the letter-box before the letters. The tit-bit will be a better reward for your dog than chasing the postman away.

Barking when the telephone rings
If you shout (bark) at your dog when it barks at the telephone ringing, you are encouraging it to bark more. It feels there is danger if you react. Get a friend to phone you at several agreed times. When the phone rings do not move and do not speak. After your friend has done this a few times your dog will no longer bark when the telephone rings.

Barking from balconies
When a dog barks from a balcony at someone passing by, it is simply asserting its dominance, firstly by looking down on humans and secondly by successfully telling them to shove off. As far as the dog is concerned, it is objecting to someone invading its territory. And even more pleasing, its barking is rewarded by the passerby walking away. Answer: ban the dog from the balcony.

Barking deterrent
Abistop is a French invention resulting from chemosensory research into the dog barking problem. It is attached to the dog's collar and automatically emits a small spray of citronella whenever the dog barks. Brief exposure to citronella immediately distracts dogs but does not cause them distress and even smells pleasant to humans. It is effective but expensive at £90. A cheaper method might be a quick squirt of water from a plant spray bottle or putting a bit of food in front of the dog's nose. It cannot eat and bark at the same time.

Commitment, Firmness, but kindness.