Pass the trials to reach the final and end up winning more crowns and be able to move up the ranks. It will get harder and harder and you will be able to get accessories depending on how many games you win.
Collect the coins along the way to fill the bar at the top left, which will give you a weapon with which you can destroy the cars in front of you. Get the highest score possible
Change lanes to avoid the cars and get a higher score. Collect coins along the way to buy different cars. If you crash you will have to start all over again from_ scratch.
Grab the turbos and aids along the road to be able to go faster and if you get next to an enemy you can knock him off the bike and thus have fewer opponents to climb more positions on the podium to get better rewards and buy different bikes or weapons.
Shift your car as close to green as possible so that the nitrous comes out much faster and better than it would otherwise. If you win the race you will get money to buy upgrades for the next races and buy different cars.