To start in front of your opponents, you have to hold R1 and X and push left or right (depending on which racer you want to start in front of.) on the left analog stick so that you will move in a 180 degree motion, so that the rear end of your car hits the side of the other racers which helps put you in front of them. If done correctly, you will start the race exactly after you do this (Does not work with motorcycles).