What three factors that should be considered when designing a car to minimise air resistance?

What three factors that should be considered when designing a car to minimise air resistance?
If you are only considering three, consider drag coefficients of the body. The type of paint and shape used are very important. The front fascia should not have an excessive amount of air pockets. A certain number are required to keep the engine cool, but they also increase drag. Also, the undercarriage should be streamlined as much as possible.