It is imperative that you carry a first aid kit.  Either purchase a comprehensive kit or assemble your own, under professional guidance.

Ensure that the kit will match your trip level - a typical small car kit is not suitable for extended outback touring.

It is important that someone in your vehicle has a working knowledge of first aid and knows how to use the kit.
 

It is highly recommended that you contact a suitable organisation (eg St Johns) and undertake formal first aid training.

  
Ensure that you carry a first aid manual.

If you are on medication, ensure that you take sufficient medication to cover your trip.

  
Consider taking spare prescriptions on longer trips.    

Ensure that any medication is correctly stored in the vehicle.