Set up a single player race in Arcade mode, difficulty doesn't matter so leave it at Normal because the only thing that changes is the top speed for yourself and the AI. The main thing that you're going to want to change is the Lap Count. Change it to 5 laps so that you have more than enough time to
completely drain and fill your boost meter twice. To fill your boost meter, you're going to need to drift or power slide around the track. To do this, you'll need to squeeze the
as you're coming up to a corner or somewhere that you feel comfortable sliding. It doesn't matter if you win but you should do so with ease with that much boost. Aston's BullDog is great all around car for speed and controlled drifting.