If police cars are after you, drive as close as you can to the side walk. Then, when you see a police car wait till it gets close to you. Finally, drive quickly away so the police cars go crashing into the wall. P.S It doesn't always work.
To drift, you have to press the brake and turn. If you don't have enough drift points (only on special drift games) you can turn around, go back to right before the start line, turn around, and keep drifting.