Start a game, rename it DRAGON, then change it back to your original name. You will start with the Dragon series (the best series) of car parts.
Press B when "Press Start" appears at the title screen.
Inspect which kind of track are you going to play on before you start. Then choose the appropriate type of tires, floats, or propellers in order to get an easy win.
If you are in urgent need of money, play a race that you can win repeatedly until you have enough money. You can get the same amount of money at the end of every attempt.
When starting a race, make sure you have oil in your car to increase acceleration. When the pre-race countdown reaches the end of "1" press Gas to get a head start boost in the race.