Watch out for your vehicle cover be it red or green. If you're red, you must pass through the red gates. When you pass through three gates successfully, the polarity is switched and you'll need to change the gates you pass through.
To activate a speed boost, hit the bottom-center of the screen. You'll then shoot off at a terrific rate, so save it for straights or parts of the course you know extremely well.
Set a fast time, chain up a combo of successful gate passes, and avoid collisions in a lap to get some very useful XP bonuses which will help you level up through the ranks.
Leveling up not only gives you access to brand-new vehicles, it also allows you to customize the appearance of your racers, adding a little cosmetic flair to your performance.