Whether your dog has one specific fear, or if they are seemingly afraid of everything, there are some steps you can take to help calm their minds and make their lives more enjoyable. Let's start at the beginning.
There are a few common causes of fear in dogs...1) genetics- some dogs are just naturally more fearful or sensitive than other dogs due to their genetic makeup. 2) Lack of early socialization- the amount of positive socialization experiences your dog requires in the early stages of its life will vary from one dog to the next. Some dogs are just more easy going and extroverted, so they do fine with minimal exposure, while others are more sensitive and will require much more positive exposure to many different stimuli throughout their lives. Emphasis on the positive exposure. Making sure the experiences are good experiences are key to socialization. 3) Learned behaviour- a bad experience can teach a dog to be afraid of a certain item. It could be something as simple as a car backfiring upon their first interaction with a man with a beard. The dog may then associate the man with a beard with a large scary noise. (It's not always this simplistic, of course). Finding the root cause of the fear is not always possible. The most common misconception is that the dog must have been abused, so that's why its afraid all the time. Or my dog is afraid of men, so a man must have abused it in the past. Although, that may very well be a possibility, 9 times out of 10, it isn't the case at all.
So what can you do about it....work on positive exposure to the fearful stimuli, while keeping your dog under threshold. Desensitizing your dog to the stimulus that scares them. Keeping them under threshold is key. What is threshold? Basically the dog's threshold is the point where your dog is reacting and no longer thinking. You won't be able to help your dog when he is in this state of mind. Don't allow them to get to that state. The more opportunity he has to practice the fearful behaviour, the more it becomes an ingrained habit. Instead, you need to stay at a distance from the scary thing, allow your dog to look at it, get their attention back on you and reward your dog. With repeated trials, he will learn that the when the scary thing is around, if I look at my owner instead, I will get a treat. Pretty soon, the scary thing will mean good things and their fear will decrease. Of course, this sounds very simplistic and there is a lot more things involved in the process, but this gives a general overview of the goal.
What if your dog is seemingly afraid of everything? Break it down and work on one thing at a time. Don't try to work on everything at once or you will set you and your dog up for failure. You will find that your dog will gain confidence as you work through their fears and the scary things will become less and less scary. Work on obedience command training. This increases your communication skills with your dog, which in turn increases your dog's confidence and its bond with you. Stick to routines. If your dog knows what to expect on a day to day basis, they will feel more secure in their environment. Learn to read your dog's body language to ensure that they are kept under threshold. If your dog is severely anxious, and not able to get under threshold, medication along with the desensitization procedure will give you the added assistance you may need. Fear is not something that you can overcome in one session, but if you put the time and effort into training your dog, he will reward you tenfold. Seeing a dog transform from a scared, anxious dog to a more happy, confident dog just warms my heart.