The most effective way to deal with rust is to prevent it from developing in the first place. Unfortunately, it's a common problem, so you may be unable to eradicate it, but there are measures you can take to help your cause.
Keep your car in a garage
Keeping your vehicle in a garage, or at least keeping it covered, will protect it from damage caused by adverse weather conditions.
Wash your car regularly
Keep the body and underside of your vehicle clean of dirt, grime, grit and salts by washing it regularly, particularly during bad weather. Pay particular attention to any pockets where water can build up, such as around the wheels.
Tackle any small rust spots early
As soon as you notice any rust developing, no matter how small, remove it, apply an anti-rust primer and repaint it. This relatively small maintenance job will save you time and money in the long run. But unfortunately, rust is a widespread problem, and it doesn't take long to spread to other parts of your vehicle.