CORR rallys: If the race has a bend at the beginning, wait until the other cars have gone then accelerate. This will get you out of the pile up at the first corner.
Increasing speed: Go for hill climb, windy point A, which is almost a long straight with some turns. Try using the toyota tacoma.
Exiting a corner: Brake early, then increase the speed carefully when exiting a corner. In races where there are multiple opponents position yourself on the left side if the next turn is a left turn and vice versa.
Selecting a car: Look for torque rather than hp/tons. A high torque can overpower a car with more horsepower. The second best car is often more easy to handle than the most powerful one. You will often get cars as prizes. Try to use them to the maximum before buying a new one.