Summarize the following:
If your dog has a major cut or a wound that is bleeding profusely, it may be best to seek vet help immediately. While you are taking your dog to the vet or animal hospital, apply pressure with a clean bandage or towel. If there is a foreign object in the wound, do not try to remove it yourself.   If the wound is not severe or bleeding quickly, you will likely have time to dress it before seeking vet help. If the wound is so minor that the dog is not scratching at it or paying attention to it, you may not even have to dress it. Just go straight to the vet. If the blood from the wound is coming out in spurts or is bright red, this could indicate arterial bleeding. Such bleeding can be life-threatening. Apply pressure to the wound and seek immediate help. Ask someone to help keep the dog in place so you can bandage the wound and wrap the shoulder. The dog should be standing so you can wrap the bandage under the dog's torso. If the dog is in pain, it may snap or bite. Even a typically calm dog can bite out of fear when hurt. To avoid this, consider using a muzzle or having someone gently but firmly hold the dog's head and neck forward while you dress the wound. If possible, before you wrap the wound try to gently clean it with a saline solution and a clean gauze or cotton pad. You do not need to extensively clean the wound at this moment. Simply flush out the opening with the solution. Dab the wound gently with clean cotton gauze. Then cut a cotton bandage to fit the size of the wound and place it directly on the open wound. Press down firmly with 1 hand to slow any bleeding. Consider wearing gloves to prevent introducing germs to the wound.

Summary:
Assess the bleeding. Keep the dog in standing position. Clean the wound. Press a cotton bandage on the shoulder wound.