Just like people, if the unthinkable happens your cat might need some first aid before you are able to get him/her to the vet. Having a cat enclosure or cat run will greatly limit the chance of your cat getting hurt or injured since they wont be running around the neighborhood at their own free will and at risk from the dangers associated with this. Despite your best efforts to look after your cat eventually they are likely to get some kind of injury so knowing some basic first aid beforehand is vital.

The most important thing to remember is to REMAIN CALM! The same as with humans, the worst possible thing you can do is fret about and get stressed; you need to remain calm so that you are able to think and to keep your cat calm also.

Disclaimer: What follows is information only regarding basic first aid for your cat. Actual medical advice should be sought from a vet for all pet first aid

Bleeding
Minor bleeding from cuts, scratches and grazes will heal quickly and easily on their own however for something more serious you should clean the wound and make sure that it doesn't get infected. very serious cuts should be treated by a vet.

Bites
This can be an issue especially in a country like Australia. If your cat is bitten by a spider or poisonous insect you might not notice straight away but may notice strange behavior a little while after the initial bite. Try to establish what it was that bit your cat and take them to the vet immediately. You should try to limit the pumping of blood from the bitten area around the rest of the body by squeezing tightly.

Burns
A burnt cat should be monitored for shock. Treat heat burns promptly by cooling the burnt area with cold water and applying a cold press. Electrical burns can be much more serious can may result in cardiac arrest. As always seek a vet immediately. 

Drowning
Cats don't like water and will generally jump away from water as quickly as possible but should your cat drown they can sometimes be revived using mouth to mouth resuscitation (or mouth to nose in this case). Close the cats mouth and gently blow air into both nostrils by covering them with your lips then removing your mouth between puffs to allow air to escape.

Injury
If your cat gets an injury to a part of its body you should get them to a vet as soon as possible. Pick your injured cat up as carefully as possible making sure to support their whole body and being careful not to twist or pull the body. Put your cat in a box or cat carrier with an open top to allow easy access. Put a warm blanket or towel on them to keep them warm

Poisoning
As is the same in humans, unless you see what your cat has been poisoned with it is difficult to diagnoise. Always try to take your cat to a vet as soon as possible and grab a sample of whatever it is you think your cat may have been poisoned with to take with you. Cats can become violent when in pain so wrap them in a towel to help restrain, this will also keep them warm.