Racing
The starting lap is the most difficult part of the race. All cars will still be packed together, causing a chaotic situation. Try to get ahead of the group of other cars as fast as possible. Destroying your opponents should be a priority. This will reward you with components that are needed to upgrade your car as well as experience points. You will also push your opponents back a few seconds.
Upgrades
It is usually better to fully upgrade a car before purchasing the next available car. The Duster, your first car, will be sufficient for the first few sets of races. However it must be upgraded for better performance. Improve its gears to make it more sturdy.
Weapons
When you are at the maximum carrying capacity for your weapons, pick up another one to get a "Charged!" bonus, which is worth fifteen experience points. Collect as many weapons as possible to earn that bonus, which will also gives your opponents less of a chance to harm you. Weapons will automatically recharge to their default amounts after you complete a lap.