Fear: a distressing emotion aroused by impending danger, evil, pain, etc., whether the threat is real or imagined; the feeling or condition of being afraid.
Life can be filled with fear causing objects, situations or events. How our canines deal with these depends on their past experiences, introduction and watching you. Often there is a negative association to something; maybe a bad thing happened at the park so your dog is on guard while there. Perhaps a large man wearing a hat scared your dog so now he is wary of hats and men. Dealing with fear can be a very sensitive affair; how you undo fear takes time, patience and understanding.
Elements in our daily life can be fearful to dogs whether they are a new puppy or just experiencing for the first time. Being that I have a new puppy I am dealing with lots of "new" things that Elsa has never seen before. In fact almost everything she is experiencing is new. She is very confident and assured; she has feared very few things so far but I'm sure there will be lots to overcome in the near future. So far she has only been concerned with a little white Bichon, a bench, the birds in a pet store and a very loud siren at a strip mall.
So what do you do if your dog displays fearful behavior? The first and most important thing is to never force; don't push, pull or cajole. You need to outwardly ignore the fear, do not feed into it. Next you need to display your own behavior of carefree and who cares attitude. For Elsa's fear of the little white fluffy dog which initially surprised me; I simply bent down beside the dog and said hello. She was bucking at the end of her leash trying to run away but as soon as she saw me saying "hi" she came to see what I was doing. I was showing her that I was not afraid and that this guy was pretty darned cute. Within a minute she was jumping on his head.
For the bench that she was afraid of I quietly sat down and put some cheerios on the edge. Again within a minute she was sitting by my side not giving the bench another thought. The birds that frightened her were loud and I knew they would be an issue. So we went into the store and I just let her take it all in. Her tail went down as she listened intently to the squawking. After several minutes of letting her see that nothing was happening I asked her for a sit which is about as solid and reliable as it will ever be. She looked up at me and sat; got her cheerio and we moved on, bird issue gone.
Your own behavior is huge; if you are a true "leader" for your dog then they will always look to you for guidance. If there is a scary noise in my yard Elsa will look to my big dogs for guidance. If they are just laying there then she will ignore the noise like they are. If she is more afraid she will come and sit by me and watch what I am doing. At that point I usually get up and putter around making it clear that the scary noise is not.
Remember, your dog is always watching you.