1. Provide better driver training.
2. Emphasize seat belt use.
3. Restrict the number of passengers, especially early on. This is particularly important because the risk of an accident goes up sharply with young drivers with passengers.
4. Make sure your teenager gets enough sleep before driving. There's good reason to think that large numbers of crashes are related to drivers who haven't slept enough.
5. Take a hard line about alcohol (and drug) use and driving.
6. Do not allow your child to ride with a new driver. This website is about your teenage driver. But, obviously, the passengers of a teenage driver are at least the same risk as the teenage driver. More here.
7. Be smart about the vehicle issue.
If you buy a vehicle for a teenager to drive: Sensible, relatively safe, and un-fun vehicle. Check crash test data.
8. Don't permit texting or other cell phone use when the car is moving.
9. Develop, require, negotiate, and enforce a written contract.
No contract=No independent driving. Period.