Find an easy race such as a drag or something short that you can win quickly. Win the race and get the money. Go back to the safe house and start the race again. Win the race to get the same amount of money again. Repeat this process as much as desired. This is quite useful when you need that extra bit of power to defeat a blacklist rival, but don't have the money for a better car or parts.

Defeat one of the opponents on the blacklist. You will get two marks to use on several different things. Do not use them on the Uniques early in the game. Instead, use them on the middle or the left Random choices. They should usually come out to either a large cash bonus or the opponent's pink slip.