Dog first aid is not unlike first aid for humans, with some differences. For one thing, your pet can not tell you that it hurts, and so they may respond to pain by trying to bite you instead. You should really have two people when trying to treat your pet, you, and someone to keep them calm and to prevent the dog from biting you. The other difference between pets and people when it comes to injuries is that you can put a bandage on an injury with a human, but your dog is not going to keep it on very long, and they are prone to licking wounds.
One of the first things you can do if your dog gets injured, is to stay calm. You pet can sense your anxiety, and therefore get excited as well You should have a first aid kit prepared for your pet, with antiseptic wipes, bandages, and even some non toxic antibiotic ointment handy. You should include a muzzle of some sort, like strips of an old pair of panty hose to tie around the snout. You are going to need some tweezers, some hemostats, as well as a pair of blunt end scissors. You will need some oral syringes, a small one for medication, or for ears, as well as a large one for cleaning wounds. Also you are going to need some sterilized water, not just to keep your pet hydrated, but also to clean the wound out. You can buy assembled kits that include these and many other things you will need.
If your dog is choking, then you will need to perform a dog Heimlich procedure on him. Regardless of the size of your dog, the first step is to check and see if you can dislodge the object from their mouth and upper throat area. If your animal is unconscious, grab their tongue and pull it forward to try to get the object out. If it is awake, be careful not to get bitten. Stick your finger in their mouth and in a sweeping motion, try to get the object out. If you can not then you need to move on to the next step. If your pet is small enough to pick up, place their spine against your chest, place both hands under your dogs waist, just below the rib cage, and put your hands together, one in a fist, just below their last rib. Thrust upwards quickly about five times, making sure it's not hard enough to injure them, then look again for the object in their mouth. Keep doing this until the object is dislodged.
For larger pets, if you can not get the object out, then lift them up by the hind legs and see if that works. If it does not, then place your pet in a standing position and with the palm of your hand, give 5 sharp blows between the shoulder blades, and check them again. Continue doing this until the object comes out. If they are unconscious, then lay your dog on its right side, and kneel with its legs towards you, place your palms on each other just under their rib cage and give five thrusts in and upwards. Check then to see if the item came out.