How to Feel Comfortable Around Big Dogs
If big dogs scare you, you can begin to feel more comfortable around them by visiting a dog park, where you can watch them from a safe distance. When you're feeling ready, approach the owner of a big dog and make sure it's okay to meet their dog. If so, let the dog come to you and then give it the back of your hand to sniff. After it has sniffed you, you can pet its sides until it becomes more comfortable with you and then you can pet its head. You might also want to have some treats handy to give a big dog and help get it to like you. Remember you should never force a dog to interact with you if it doesn't want to otherwise it may become aggressive.
Talk to the owner first. When around a big dog, be sure to greet and talk with the owner first. This should be done while completely ignoring the dog. Your positive interactions with the owner will signal to the dog that you have a positive, non-threatening presence. Avoid making eye contact. Staring directly at a dog can be seen as a challenge or a threat. Consequently, try to avoid making eye contact with the dog. Also, try not to stand facing the dog, but stand with your body sideways. Standing with your body sideways is less threatening, and will encourage the dog to want to meet you. Stay calm. When talking with the owner, speak in a calm, soothing tone. This will signal to the dog that you are a calm, non-threatening presence. If you seem too excited, it could make the dog excited and lead to an unpleasant greeting, like the dog jumping on you. On the other hand, dogs can sense fear, as well. If the dog senses that you are fearful, it might respond in an aggressive manner.  An overly excited tone can also trigger the dog's flight or fight instinct. Do not baby talk to the dog either. Some dogs regard this energy as weak, and are more likely to jump or pounce on you. Let the dog approach you. Always let the dog approach you first. This will allow the dog time to adjust to having you in its space, and become more comfortable with you. If a dog is comfortable with you, you are more likely to be comfortable around the dog. If a dog is shy, but still approaches you, do not talk to the dog or make eye contact with it. Let your hand hang by your side so the dog can sniff it. Offer the back of your hand to sniff. Once the dog has approached and sniffed you, then it is ok for you to offer your hand for it to smell. When offering your hand, offer the back of your hand with your fingers closed, i.e., a relaxed fist position. Pet their sides, not the head. When petting the dog, always pet the sides of the dog first. Try to avoid petting its head. A general rule of thumb is to start from the body and move towards the head. For example, begin by touching the dog's back. If the dog is comfortable with light touch, then begin to pet its back. If the dog becomes comfortable with you petting its back, then you can move toward the back of its head and ears. Read the dog's body language. By knowing how to read a dog's body language, you can deal with the dog appropriately. This way, you can avoid any negative interactions, such as a growl or a bite. A dog that indicates that it is shy or not ready to meet you should be left alone and given space. Shy dogs will move away or lean away to create more space. They might also have their head lowered with their tail tucked between their legs. A raised paw, yawning, and a licking of its lips accompanied with a lowered head are also signs that the dog is unsure of you. Don’t force the dog to do something it doesn’t want to do. If the dog does not want to interact with you, never force it to. Forcing the dog to interact with you might cause it to growl or bite you. If the dog is standoffish, then give it space. By giving it space, it will understand that you respect it, and the dog will be more likely to approach you when it is ready. Give the dog a treat. Treats are always a great way to get a dog to like you, and thus, be comfortable around you. This way, you will also be comfortable around the dog. When giving a dog a treat, do not dangle the treat in the air. This can cause the dog to stand on its hind legs or jump up to retrieve the treat. They have less control over the mouths when jumping up to retrieve a treat. Instead, place the treat in the palm of your hand. Make sure your palm is flat. Then, bring the treat close to the dog's face, i.e., under its mouth or at chest level. Let the dog lick the treat from your hand. Visit a dog park. With a friend or a family member, visit a nearby dog park. You do not need to go inside the dog park. Instead, you can stand outside of the park. Watch how the dogs interact with each other and the people. Particularly, watch the larger dogs. Observe how their interactions aren't any different than the interactions medium and small dogs have. Bring some dog treats with you. Try giving a large dog a treat through the fence if their owner allows. You can also have your friend give the dog the treat. Watch how the dog interacts with your friend. Then, try to give the dog a treat. Gradually expose yourself to large dogs. To overcome your fear of large dogs, try exposing yourself to small or medium dogs first. By becoming comfortable with small and medium dogs, you can learn how to interact and be more comfortable around bigger dogs. Instead of meeting large puppies, expose yourself to larger dogs that are older and more mature. Older dogs are relaxed, and are typically less interested in interacting with other people. For example, they are less likely to run up to you, jump on you, and follow you around. Practice breathing techniques. Breathing and relaxation techniques will help you regain control of your emotions when you are in the moment. Also, come up with a mantra that you can repeat to yourself to calm your nerves. When you feel your body becoming tense and your heartbeat growing faster, relax your shoulders and begin to breathe in and out. Instead of focusing on the dog, focus on your breathing. Inhale, hold your breathe for a couple seconds, and then exhale. Repeat a positive mantra to yourself, like, "I am in control and I am not afraid of dogs. I know how to handle dogs." 
Talk to the owner first. Avoid making eye contact. Stay calm. Let the dog approach you. Offer the back of your hand to sniff. Pet their sides, not the head. Read the dog's body language. Don’t force the dog to do something it doesn’t want to do. Give the dog a treat. Visit a dog park. Gradually expose yourself to large dogs. Practice breathing techniques. 